Is Task Board Customization Beneficial? - An Eye Tracking Study

08/01/2017 ∙ by Oliver Karras, et al. ∙ uni hannover 0

The task board is an essential artifact in many agile development approaches. It provides a good overview of the project status. Teams often customize their task boards according to the team members' needs. They modify the structure of boards, define colored codings for different purposes, and introduce different card sizes. Although the customizations are intended to improve the task board's usability and effectiveness, they may also complicate its comprehension and use. The increased effort impedes the work of both the team and team externals. Hence, task board customization is in conflict with the agile practice of fast and easy overview for everyone. In an eye tracking study with 30 participants, we compared an original task board design with three customized ones to investigate which design shortened the required time to identify a particular story card. Our findings yield that only the customized task board design with modified structures reduces the required time. The original task board design is more beneficial than individual colored codings and changed card sizes. According to our findings, agile teams should rethink their current task board design. They may be better served by focusing on the original task board design and by applying only carefully selected adjustments. In case of customization, a task board's structure should be adjusted since this is the only beneficial kind of customization, that additionally complies more precisely with the concept of fast and easy project overview.

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1 Introduction

Agile software development is a general term for a set of development approaches which focus on social aspects. These approaches aim at increasing the developers’ productivity, delivering working software in time and minimizing the risk of failure within software projects [27]. The core concept of agile development is based on fundamental values which are concretized by defined principles that are in turn fulfilled by certain practices [6].

eXtreme programming (XP) [5] and Scrum [24] are the most commonly used and combined agile approaches [3, 20]. One practice of XP is the informative workspace. According to Beck and Andres, this practice is about how to “make your workspace about your work. An interested observer should be able to walk into the team space and get a general idea of how the project is going within seconds” [5, p. 39f.]. Cockburn [8] provides a similar concept of the so-called information radiator. “An information radiator displays information in a place where passerby can see it” [8, p. 114]. An information radiator has to fulfill two features – representing information that changes over time, and requiring very little effort to view the display. In total, an implementation of these two concepts must be easy-to-use and offer a fast overview with minimal effort [22].

One implementation of both concepts is the task board [25]. It is one key artifact of agile development [3, 14] which serves a dual purpose of supporting a team’s work organization and constituting at a glance how much work is left [10, 18]. Additionally, a task board allows communication and collaboration since it tracks and visualizes the software development process and thus simplifies its accessibility for everyone [17, 20].

Although the original task board design of Cohn [10] provides a clear overview, teams tend to customize their own [26]. Sharp et al. [27] analyzed six different mature XP teams and their task boards. They identified that the teams’ task boards were consistent in terms of usage, but not regarding a particular design. The different task board designs resulted from combinations of various customizations like modified structures, individual colored codings and changed card sizes. Customization itself is not serious since a task board can be easily and flexibly adjusted due to its physical nature [13, 26]

. Additionally, agile approaches involve customization by offering corresponding degrees of freedom

[20, 28]. Furthermore, any adjustment of a task board by an agile team according to its needs is plausible since the team members work with it every day [26].

However, multiple combined customizations complicated the maintenance and comprehensibility of a task board. In particular, the increased effort impedes the work of a team as well as team externals with a customized task board [13, 15, 27]. Thus, the underlying practice of a task board as an informative workspace for fast and easy project overview for everyone gets lost.

While the tight social and technical cohesion found in mature agile teams are not disputed, the effect of single practices like the informative workspace is little understood [27]. Berczuk emphasizes that “any team is best served by following the rules of the agile method with as few adjustments as possible” [7, p. 6]. Corresponding to Pikkarainen et al. [20], adoption and change of agile practices are aspects of future studies. Therefore, we investigated whether specific single task board customizations contribute to a task board’s usage in comparison with an original task board design. As an example, we focused on the identification of a particular story card as one main task of using a task board.

We conducted an eye tracking study to compare an original task board design corresponding to literature [10, 17] with three customized ones. Each customized task board differs exactly in one single aspect from the original one, such as modified structures, individual colored codings, or changed card sizes. Each modification could contribute to achieving a better overview of a task board in order to identify a particular story card faster. In our study, we observe whether a particular task board customization improves the work with a task board. These results identify whether specific kinds of customization are beneficial or not for a task board’s usage. Our findings can help agile teams to rethink their current task board design in order to improve it.

The contribution of this paper is the insight that modified structures are the only kind of customization that shortens time to identify a particular story card. Individual colored codings and changed card sizes even have detrimental effects on the performance. Agile teams should reconsider their current task board designs. They may be better served by focusing on the original task board design and applying carefully selected adjustments. A task board’s structure should be adjusted since this kind of customization is beneficial and complies with the agile practice informative workspace.

This paper is structured as follows: Section 2 discusses related work. We describe the task board and its major kinds of customization in section 3. In section 4, we report our eye tracking study and document its findings, which we discuss in section 5. Section 6 concludes the paper.

2 Related Work

2.1 Task Board: Key Artifact of Agile Software Development

Several researchers investigated the task board’s usage and role in the agile software development process.

Sharp et al. [25] systematically consider the use and role of story cards and a task board in one mature XP team. Based on story cards and the task board, the authors analyze the team’s collaborative work by using the distributed cognition framework. Thus, the information flows in, around and within the XP team can be substantiated to answer “what if” questions regarding changes to the story cards’ and task board’s form to illustrate consequences for the teamwork. Sharp and Robinson [26] extend the previously mentioned study on three mature XP teams. Their results show significant similarities between the teams’ usage of story cards and task board, but not in their particular designs. After discussing the importance of a physical representation of both artifacts, the authors highlight important aspects that need to be taken into account for technological tool-support of agile development. In a further study, Sharp et al. [27] investigate the role of story cards and a task board from two complementary perspectives: a notational and a social one. Based on both perspectives, they explain that these two physical artifacts are important key properties of successful teams. Any attempt to replace these artifacts with technological support needs to take into account the complex relationships between both perspectives and the artifacts. Petre et al. [18] consider the use of public visualizations, i.e. story cards and task boards, in different software development teams. In a number of empirical studies, the authors observe differences in the use of paper and whiteboards between traditional and agile teams. The findings are used to identify possible implications of these differences for software development in general. Liskin et al. [15] explore the use and role of story cards and task board within a Kanban project. Their findings reveal that despite a task board for requirements visualization and communication some requirements are still too implicit and caused misunderstandings. Katsma et al. [14] investigate the usage of software- and paper-based task boards in globally distributed agile development teams. They conclude that paper-based task boards currently offer many advantages compared to its software-based solutions. By applying the media synchronicity theory, Katsma et al. [14] explain the current use and future development of software tools to support globally distributed agile development teams. Perry [17] reports his experiences about transparency problems in agile teams due to difficulties in the transition from a physical to electronic task board. He discusses the advantages and disadvantages of physical and electronic task boards. Based on his observation, he concludes that both task board types have their place in team collaboration. However, the simple power and utility of physical task boards should not be neglected. Hajratwala [13] observes the creation and evolution of various task boards over time in different projects. He explains the reasons why the task boards evolved, and recommends key attributes that a task board should have.

The previous investigations focus on both the usage and role of story cards and task boards in agile software development. The main focus is on the general work with a task board and its importance for agile development. Additionally, different task board designs and their evolution over time are presented. Although differences in the designs were recognized, none of the researchers considered its possible impact on work with this artifact. Our paper addresses this topic by investigating whether task board customization is beneficial or not.

2.2 Viewers’ Consideration of Software Development Artifacts

There are already several researchers who used eye tracking to investigate a viewer’s consideration of a respective software development artifact.

Ahrens et al. [1] conducted an eye tracking study to analyze how software specifications are read. They identified similar patterns between paper- and screen-based reading. The results contribute awareness by considering readers’ interests based on how they use a specification. Gross and Doerr [11] performed an explorative eye tracking study to investigate software architects’ information needs and expectations from a requirements specification. The results allow first insights into the relevance of certain artifact types and their notational representations. Gross et al. [12] extended their previously mentioned eye tracking study by analyzing information needs and expectations of usability experts. Based on the findings, the authors introduced the idea of a view-based requirements specification to fulfill needs of different roles in software development. Santos et al. [23] evaluated the effect of layout guidelines for goal models on novice stakeholders’ ability to understand and review such models. They identified no statistically significant differences in success, time taken or perceived complexity between tasks conducted with well and badly designed model layouts. Ali et al. [2] applied eye tracking to the verification of requirements traceability links. Their data analysis allowed the identification and ranking of developers’ preferred source code entities. Thus, the authors defined two weighting schemes to recover traceability links combined with information retrieval techniques.

All previous studies apply eye tracking to analyze how specific software development artifacts are read by persons with different functions. We follow this approach by using eye tracking to investigate the work with a task board. Our study specifically focuses on the impact of different task board customizations on a task board’s usage by team externals respectively new team members.

3 Task Board: Structure and Content

The task board’s origins are the informative workspace practice of Beck and Andres [5] as well as the concept of information radiator by Cockburn [8]. They present first ideas of story cards pinned on a wall or whiteboard. In their books, they offer possible implementations of these concepts.

Cohn [10] describes a first concrete task board design in his book “

Agile Estimating and Planning

”. According to his definition, a task board consists of up to seven columns to track and visualize a team’s progress in development. The seven columns are:

  1. Stories: A backlog of all story cards

  2. To Do: All task cards to implement particular story cards

  3. Tests Ready: Status of a story cards’ acceptance tests

  4. In Process: Task cards developers have signed up for

  5. To Verify: Implemented task cards that need to be verified

  6. Hours: Total working hours remaining for particular story cards

  7. Done: All implemented and verified task cards

Furthermore, Cohn [10] defines that a task board includes one row for each story card. Each row contains all task cards that are related to the corresponding story card. According to Cohn [10], the columns Tests Ready, To Verify, Hours and Done are optional.

3.1 Task Board Customizations

Based on the previously mentioned findings in literature, we considered further research papers about the design and content of task boards. Additionally, we analyzed different task boards with respect to their design in online galleries of team spaces [29, 4, 19]. Thus, we identified three major kinds of customization: modified structures, individual colored codings, and changed card sizes.

Modified structures are changes regarding the amount and usage of a task board’s rows and columns. Petre et al. [18] describe a task board as a vertical surface for story cards. This task board has a codified structure to indicate a story card’s status. Other researchers [21, 22, 17] report in greater detail about this codified structure. Pries-Heje and Pries-Heje [21] focus on a task board for Scrum, which consists of the four columns Backlog, Task in Progress, Done, and Done Done corresponding to their description. A similar task board structure is mentioned by Rubart and Freykamp [22]. The columns of this task board are named Selected Product Backlog, Tasks To Do, Work In Progress, and Done. Perry [17] also reports that a simple task board has four columns called Story, To Do, In Progress, and Complete.

All descriptions have in common that the task board structure consists of the same four columns with only slightly different labels. However, none of these researchers mentions the use of rows on a task board. We could identify two variants for the use of rows based on our consideration of team spaces in online galleries. The first variant uses one row for each story card, which corresponds to Cohn’s definition [10]. The second one uses rows in specific columns like To Do and Work In Progress to visualize the assignment of developers to story cards. The comparison of these insights with Cohn’s original task board structure [10] shows clear differences regarding the amount and use of a task board’s rows and columns between theory and practice.

Individual colored codings are colored cards and markers with arbitrary meaning which need to be memorized. Several researchers report the widespread individual use of colored codings on task boards. Katsma et al. [14] describe the use of different colored cards to indicate various card types, e.g. red for bugs cards. Liskin et al. [15] mention colored markers on cards to represent assigned developers. Sharp et al. [25, 26, 27] observe the use of colored markers and cards as status indicators and card types in four mature XP teams. These findings correspond to our observations of the task boards presented in the online galleries. Even though we cannot clarify the exact meanings of the used colored codings, we observe that their use is widely scattered.

Changed card sizes consider the size of story cards which are used to write down user stories and display them on the task board. The size of story cards has a wide range. Azizyan et al. [3] as well as Katsma et al. [14] report about story cards the size of sticky notes or post-its. In contrast, Perry [17] and Sharp et al. [27] state that a story card’s size can be up to an index card of inches. These insights coincide with our observations of the online galleries. We identified the same range of card sizes from post-its up to index cards.

3.2 Task Board Designs

In consideration of the previously described findings, we developed four task board designs for our eye tracking study. These designs are based on a dataset of real story cards from a completed software project. While one task board design is similar to Cohn’s initial definition of a task board design [10], each of the other designs takes one of the three major customizations into account.

During the design development, we took into account that all task boards represent the same content, except for exactly one specific difference according to the customizations. Figure 1 represents an overview of our four task board designs. All task boards have four columns, labeled with Stories, Task To Do, W.I.P (Work In Progress), and Done. These labels are adopted from the original task board of the completed software project whose story cards were used. We decided to change as little as possible from the original dataset. Therefore, we retain the labels of the task board since they are similar to the previously mentioned ones. Furthermore, these four columns cover all three obligatory columns corresponding to Cohn’s definition [10].

(a) Task board: Original design
(b) Task board: Modified structures
(c) Task board: Individual colored codings
(d) Task board: Changed card sizes
Figure 1: Task board designs

Figure 0(a) presents the task board with an original design which is similar to Cohn’s definition [10]. This task board does not have Cohn’s row structure [10] since the used dataset of real story cards did not consider this aspect. Therefore, the story cards could not be grouped to achieve a reasonable row structure.

Figure 0(b) shows the task board with modified structures. We decided to use the second variant of additional rows over specific columns since Cohn’s row structure [10] was not applicable to the used dataset. We did not add additional columns to change only one structural aspect. Thus, we added rows over the columns Task To Do and W.I.P. to visualize the assignment of developers to story cards. Each row starts with a letter that represents one developer.

Figure 0(c) represents the task board with individual colored codings. In accordance with literature [15, 25], we added colored markers on the right lower corner of the story cards. Each of the three colors (green, orange and blue) represents one developer and his assignment to the corresponding story card.

Figure 0(d) illustrates the task board with changed card sizes. We decided to minimize the story cards to sticky note size (ca. inches), since story cards have originally index card size (ca. inches).

All task boards have the same amount of handwritten story cards whose content is based on the real dataset. The first three task boards (see Figure 0(a), Figure 0(b), and Figure 0(c)) contain 40 story cards of index card size. The last task board (see Figure 0(d)) contains 40 story cards of post-it note size. While the amount and general position of the story cards are the same in each column and task board, we shuffled the story cards before placing them on the task boards. Thus, we achieved a random placement regarding the story cards’ content and no task board equals exactly any other.

4 Eye Tracking Study

The aim of our eye tracking study was to understand whether task board customization facilitates identifying a particular story card faster compared to an original task board design. We proceeded to achieve this aim by comparing the original task board design with each of the three task board customizations. Such an investigation enables us to judge whether the original task board design or the respective task board customization should be preferred. We were interested in answering the following research question:

  • [leftmargin=9mm]

  • Does the respective task board customization facilitate identifying a particular story card faster compared to the original task board design?

To answer the research question, we tested the following hypotheses for each of the three task board customizations:

  • [leftmargin=8mm]

  • There is no speed difference in identifying a particular story card between the original task board design and the respective task board customization.

  • There is a speed difference in identifying a particular story card between the original task board design and the respective task board customization.

4.1 Study Design

In this study, we performed three separate within-subjects experiments with counterbalancing. The dependent variable was the task completion time for identifying a particular story card. The independent variable was the task board design with two levels: the original task board design and one of the three task board customizations. We measured the task completion time by observing the participants with the SMI Eye Tracking Glasses111https://www.smivision.com/eye-tracking/product/eye-tracking-glasses/. Each experiment represents a scenario in which the participant joins an ongoing development project as a new team member who has to work with the existing task board. We decided to focus on the perspective of a new team member since a task board should support a fast and easy project overview for everyone, i.e. the team and team externals respectively new team members. If a new team member already benefits from a customization, a whole team should also benefit from it.

We analyzed task completion times with a two-tailed paired samples -test at a significance level of . This allows us to determine whether the respective task board customization leads to a statistically significant speed difference in identifying a particular story card compared to the original task board design. Thus, we can identify whether a particular task board customization is beneficial for a task board’s usage. An existing speed difference would allow us to reject , while a missing one would not allow such a rejection.

4.2 Study Procedure

The eye tracking study was carried out with participants consisting of undergraduate and graduate students of computer science. All participants had basic knowledge about agile software development and were close to the next step in graduation. Thus, they represent potential new team members in a software development team, which corresponds to our target population.

All in all, the whole eye tracking study with all three experiments was carried out within three months. Each experiment compared the original task board design with one of the three major task board customizations. We randomly assigned each participant to one of the three experiments. In each experiment, we conducted separate sessions each with one of the assigned participants. Each session included an introduction to the experiment with its task of considering two task boards. In this context, we explained the basic concept of a task board. Depending on the experiment, we assigned the letter “J” (see Figure 0(b)) respectively the color “green” (see Figure 0(c)) to the participant since the task boards with modified structures respectively individual colored codings required the assignment of a row or color to the participant. After the calibration of the SMI Eye Tracking Glasses for the participant, we captured their examination of the task board. We repeated the same process for the second task board design.

4.3 Analysis and Results

Table 1 shows the measured task completion times of each participant for the particular experiment and respective task board design. The first five subjects of each experiment (see Table 1, Group ) received the original task board design first and then the customized one. The other five subjects of each experiment (see Table 1, Group

) received the designs in reversed order. For each experiment, we verified that the data is normally distributed by applying the

Shapiro-Wilk test. Subsequently, we performed the two-tailed paired samples -tests at a significance level of . Thus, we can determine whether an observed difference exists due to the test conditions or by chance. Additionally, we calculate Cohen’s which is the most common type of effect size for -tests that indicates whether or not the difference between two groups’ mean is large enough to have practical relevance independently from statistical significance.

Subj. Experiment 1 Subj. Experiment 2 Subj. Experiment 3
Original Structures Original Codings Original Cards

Group 1

P1 16 10 P3 16 15 P4 10 11
P2 18 4 P14 16 22 P5 13 27
P11 16 11 P15 11 12 P24 30 36
P12 12 9 P16 10 9 P25 4 19
P13 19 4 P17 13 16 P26 19 18

Group 2

P6 18 10 P18 12 20 P23 22 12
P7 8 16 P19 13 16 P27 9 19
P8 12 9 P20 11 13 P28 19 28
P9 13 15 P21 5 6 P29 17 27
P10 18 10 P22 10 14 P30 12 16
Mean 15.0 9.8 Mean 11.7 14.3 Mean 15.5 21.3
SD 3.6 3.9 SD 3.2 4.7 SD 7.5 7.9
Table 1: Experiment results – Task completion time [s]
Experiment 1 2 3
Calculated -2.39 2.86 2.41
from table
2.26
Calculated 0.04 0.02 0.04
Result Significant Significant Significant
Cohen’s 0.76 0.90 0.76
Table 2: Two-tailed paired samples -test

In Table 2, we present the results of our conducted two-tailed paired samples -tests and their effect size .

The analysis of the first experiment yields a significant difference in the task completion times for the original task board design () and the modified structures (); . Hence, can be rejected for the first experiment. Modified structures shorten time to identify a particular story card compared to the original task board design. The value of Cohen’s is , which is close to the threshold of for a large effect [9]. Hence, the identified difference has almost large practical relevance.

The -test of the second experiment shows a significant difference between the task completion times for the original task board design () and the individual colored codings ();

. The null hypothesis

can be rejected for the second experiment. Consequently, the original task board design allows to identify a particular story card faster compared to the individual colored codings. Cohen’s is and thus greater than the threshold of for a large effect [9]. The determined difference between the individual colored codings and the original task board design has large practical relevance.

The results of the third experiment also show a significant difference in the task completion time for the original task board design () and the changed card sizes (); . Consequently, we can reject . This leads to the insight that changed card sizes increase the required time for identifying a particular story card compared to the original task board. The calculated effect size is and thus close to the threshold of . We identified a difference between changed card sizes and the original task board design that has almost large practical relevance.

4.4 Interpretation

Our findings provide insights with respect to the influence of task board customizations in comparison with an original task board design. Whereas modified structures shorten time to identify a particular story card, individual colored codings and changed card sizes increase the required time.

The performed -tests substantiate that there is a statistically significant difference between the respective task board customization and the original task board design. Our results indicate that customizing a task board’s structure supports its usage. In case of customization, agile teams should focus on adjusting the structure of a task board according to their needs. Since this customization supports the work of new team members who are unfamiliar with the task board, we assume that a whole team will also benefit from it. Such a customized task board provides a fast and easy project overview for everyone, i.e. the team and team externals respectively new team members. Thus, the task board complies more precisely with the agile practice informative workspace.

However, according to our results, not every customization is beneficial for a task board’s usage. Adjustments on story cards such as individual colored codings or changed card sizes lead to an increased amount of time to identify a particular story card. Even though these two kinds of customization do not necessarily support a task board’s usage, they are extensively applied in practice by agile teams [15, 25, 26, 27]. Therefore, our findings are in conflict with the observed widely distributed use of these customizations.

In total, we identified a statistically significant difference in each of the three experiments. Each difference indicates that one of the two compared task board designs (customized vs. original) allows identifying a particular story card faster. All findings have an almost large effect size that emphasizes their practical relevance. According to our results, modified structures should be preferred compared to the original task board design, which is, in turn, preferable to individual colored codings and changed card sizes. Hence, the original task board design is a good solution. In case of customization, however, agile teams may be better served by adjusting their task board’s structure instead of its story cards. As an answer to our research question, we can summarize:

  • We identified that only the modified structures allow identifying a particular story card faster compared to the original task board design. Both of the other customizations result in an increased amount of time. Hence, adjusting a task board’s structure is the only beneficial option of all investigated customizations.

4.5 Threats to Validity

In the presented eye tracking study, we considered threats to construct, external, internal and conclusion validity corresponding to Wohlin et al. [30].

Construct validity: We selected the content for the story cards from a completed software project. All task boards (see Figure 1) were based on this content. Thus, we have a mono-operation bias since we only use one dataset for the task boards’ content. As a consequence, the constructed task boards do not convey a comprehensive overview of the task boards’ complexity in practice. However, we expected that the amount of handwritten story cards and their different arrangement on each task board result in sufficient realistic complexity for the participants. Another threat to validity was the participants falsely reporting having finished. Our experiments required the exact measuring of the task completion time. However, people are afraid of being evaluated and they are inclined to convey the impression of being better than they really are. Therefore, this human tendency endangered the outcome of our experiment. We counteracted this threat by using eye tracking combined with an additional acoustical statement of the participants when they identified the particular story card. Thus, we could determine the exact task completion time of each participant beyond doubt. The single use of eye tracking is a further threat to validity. This mono-method bias is problematic since it only allows a restricted explanation of our findings. However, we focused on an objective measure instead of a subjective one since objective measures can be reproduced more easily and are thus more reliable. The given task of identifying a particular story card caused an interaction of testing and treatment. The comparison of task boards with the given task could imply to find the story card as fast as possible. Even though we did not mention to measure task completion time, the participants could be aware of the time as a factor. Instead of understanding the task board designs, they could only have tried to be as fast as possible. We mitigated this threat to validity by using eye tracking. Thus, we could observe how the participants examine the task boards and make sure that all of them took the respective design into account.

External validity: The choice of involving almost graduated students as participants, and the use of data from a completed software project produced a good level of realism. At the same time, the experimental setting endangered the external validity since the environment was different from the real world. None of the task boards had true pragmatic value for the participants since none of them had a genuine working task with the task board. Future evaluation should be done on real industry projects with team members that truly work with the task board.

Internal validity: In our eye tracking study, the three experiments were distributed over three months altogether. This large period of time could have an effect on the participants’ motivation to contribute to our study. However, we could not compare all task board designs within one experiment due to the use of eye tracking, which is time-consuming as well as exhausting for the participants. A single session with one participant required as much as minutes for the comparison of two task board designs. Additionally, we could mitigate possible learning effects since all task board designs equaled one another except for exactly one specific difference with respect to the corresponding customization.

Conclusion validity: We decided to use eye tracking to improve the reliability of our results since an objective measuring is easier to reproduce and it is more reliable than a subjective one. Additionally, we only selected students as participants who were close to their graduation. Hence, they form a more homogeneous group which counteracts the threat of erroneous conclusions. Therefore, we mitigated the risk that the variation due to the subjects’ random heterogeneity is larger than due to the investigated task board designs.

5 Discussion

This presented work investigates the task board as one implementation of the agile practice informative workspace and the benefit of task board customization.

Although agile teams use task boards in a similar manner, they tend to customize their task boards according to their needs. Combined customizations such as modified structures, individual colored codings, and changed card sizes lead to complexity, which impedes a task board’s maintenance and comprehensibility. The increased effort is in conflict with a task board’s underlying agile practice of fast and easy project overview for everyone, i.e. the team and team externals respectively new team members. We performed an eye tracking study to analyze whether there is a significant speed difference in the time required to identify a particular story card between the original task board design and the respective task board customization.

We contribute the insight that only modified structures improve a task board’s usage. In contrast, individual colored codings and changed card sizes did not improve performance beyond the original design.

The modified structures are the only beneficial customization. We assume that the additional rows improve the arrangement of the story cards. Spatially close object seems to be grouped since they are perceived as belonging to each other. This effect is called law of proximity, which is part the Gestalt Principles [16]. The additional rows influence the story card’s visual appearance by position without further support. The story cards’ improved proximity simplifies a viewer’s consideration of the task board. This finding can help agile teams to rethink their task board in order to improve it. They may be better served by focusing on the original task board design and by only adjusting its structure according to their needs. Thus, they can create a task board which complies more precisely with the concept of fast and easy project overview for everyone.

In contrast, individual colored codings and changed card sizes are not beneficial. The missing benefit of individual colored codings is caused by a counteracting effect of combined laws of the Gestalt Principles. According to the law of similarity, using colors for similar objects supports the visual appearance of belonging together. At the same time, the story cards’ spatial arrangement complies with the law of proximity. The colored markers are more difficult to perceive since the law of proximity dominates the law of similarity. Therefore, individual colored codings do not provide a benefit for customizing a task board. The changed card sizes are not an improving task board customization, either. According to our results, a viewer’s effort increases by considering and recognizing smaller story cards to identify a particular one. Smaller story cards are more difficult to perceive and read, which complicates a task board’s clarity. Thus, changed card sizes provide no benefit, either.

The impact of the different task board designs on the performance of a single team is low. Even if a team member identifies times a day a story card with an average saving of seconds per identification, his total saving would only be minutes per workday. The benefit of our results is the finding that the original design of a task board by Cohn [10] with its underlying agile practices constitutes already a good solution for a single team to be productive. Even though agile approaches offer corresponding degrees of freedom for customization, in the worst case each team of a company has its own specific task board design. Due to the wide variety of customization options, the individual task boards complicate the collaboration across teams and the work of team externals. Thus, the collaboration performance of multiple teams, as well as the work of team externals, can be improved by focusing on one consistent and beneficial task board design.

All in all, we can conclude that not each kind of task board customization is beneficial. Based on our findings, we agree with Berczuk [7]: Teams are better served by adjusting their task boards as little as possible. As a consequence, agile teams should rethink their current task board design with respect to the applied customizations. The original task board design (see Figure 0(a)) is already a good solution. However, if customization is desired, teams should focus on adjusting a task board’s structure since only this kind of customization improves the use of a task board according to our results.

6 Conclusion

This work contributes the insight that not every kind of task board customization is beneficial. Agile teams tend to extensively customize their task boards according to their needs [27]. However, the use of modified structures, individual colored codings, and changed card sizes impede work with a task board. Thus, task board customization is in conflict with the agile practice of fast and easy project overview for everyone, i.e. the team and team externals.

We performed an eye tracking study consisting of three separate experiments comparing an original task board design with each of three identified major task board customizations. Based on these results, we identified statistically significant differences in all three experiments. These findings show that modified structures such as additional rows support a task board’s usage with respect to the used exemplary main task of identifying a particular story card. In contrast, individual colored codings and changed card sizes do not improve performance beyond the original design.

Our work points to the conclusion that agile teams should rethink their current task board design. They may be better served by focusing on the original task board design and applying carefully selected adjustments. In case of customization, teams should adjust the task board’s structure since this is the only beneficial kind of customization. Additionally, such a customized task board design complies more precisely with its implemented agile practice.

Acknowledgment

This work was supported by the German Research Foundation (DFG) under ViViReq (). We follow ethical guidelines of the Central Ethics Commission of our university. They regulate subject information and rights. Since recognizable persons should not be visible on distributed video, our data is archived internally for future reference.

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