, can perform dozens of different tasks, such as finding directions and making restaurant reservations. These are the tasks that the VA developers expected to be the most widely used. However, every VA user can probably think of one or more other tasks that they would like their VA to help with, which the developers have simply not implemented yet. The unavailable tasks are as varied as the users. Thus, the demand curve for VA tasks has a very long and heavy tail of unsatisfied demand. The capabilities of currently available VAs represent only a tiny fraction of their potential. Even the available tasks are often implemented differently from how users would prefer.
This situation is unavoidable given how VAs are currently developed. There will never be enough VA developers to customize VAs in all the ways that users would like. The only way to close the gap between what VAs can do and what users want them to do is to enable non-technical end-users to teach new tasks to their VAs. Many users would be willing and able to do so, if it were as quick and easy as teaching a person.
The most common way to teach a person a relatively simple new task is to describe the task and then demonstrate how to do it. For decades, researchers have been trying to build computer systems that can be taught the same way. Their efforts comprise a body of work most commonly referred to as “programming by demonstration” (PBD). 444“PBD” is an unfortunate name, because most of the non-technical users that can benefit from it are reluctant to attempt anything with “programming” in its name.
|finite set of tasks||Siri, Cortana, et al.|
|domain-restricted set of tasks||PLOW et al.|
The simplest kind of PBD system creates and runs programs with no variables, colloquially known as macros. The absence of variables, which also implies the absence of loops and conditionals, makes it easier for non-programmers to understand and use macros. Nevertheless, macros see little use outside of special environments such as text editing software, because there are relatively few situations in which a program without variables can be useful.
To increase the usefulness of PBD, researchers have attempted to build systems that can be taught more powerful classes of programs, all the way up to Turing-equivalent systems with variables, loops, and conditionals (e.g., see [5, 6] and references therein). Invariably, such attempts run into the limitations of the current state of the art in natural language understanding. At present, the only known way for computers to deal with the richness of language that people use to describe complex tasks is to limit the tasks to a narrow domain, such as travel reservations or messaging. For example, the PLOW system  is powerful enough to learn programs with variables, loops, and subroutines. Yet, it can learn tasks only within the task domains covered by its ontology. In order to demonstrate PLOW’s ability to learn tasks in a new domain, its authors had to manually extend its ontology to the new domain. To the best of our knowledge, all previous PBD systems with variables are similarly limited to at most a handful of task domains.555From the point of view of most users, who do not have access to the developers.
The class of variable-free programs and the class of Turing-equivalent programs are the two extremes on a continuum of expressive power. However, most of the tasks available from today’s most popular VAs can be expressed by programs that are in another class between those two extremes. These programs are in the “non-branching” class, where programs can have variables but cannot have loops or conditionals. Judging by the popularity of VA software, a very large number of people could benefit from a VA that can be taught new non-branching programs by its end-users.
This paper presents Helpa, a system that can be taught non-branching programs via PBD. We have developed a way to teach such programs without any prior domain knowledge, which works surprisingly well in most cases. Therefore, Helpa imposes no restrictions on the domains in which users can teach it new tasks. We believe that Helpa’s innovative trade-off of expressive power for domain-independence occupies a sweet spot of very high utility, compared to the other classes of VAs in Table 1. In addition, our usability study showed that Helpa’s design makes it possible for end-users to teach it many new tasks in less than a minute each — fast enough for practical use in the real world.
Following , we shall refer to the teachable component of a VA as an instructible agent (IA), and the challenge of building an IA as the IA problem. After formalizing this problem in the next section, we shall describe our proposed solution. We shall then describe some of its current limitations, which explain why we claim that Helpa can learn only “most tasks”, rather than “all tasks”, in Table 1. Lastly, we shall describe a usability study that we carried out to evaluate Helpa’s effectiveness.
2 The Instructible Agent (IA) Problem
The IA problem is to build a system that can correctly execute a task expressed as a previously unseen natural language command. We shall put aside the question of what counts as natural language by accepting any string of symbols as a command. It is more challenging to operationalize the notion of executing a task.
Every PBD system interacts with a particular user interface (UI). It records the user’s actions in that UI when a user is demonstrating a new task for it to learn. It mimics the user’s actions in that UI to execute tasks that it has learned. Reliably interacting with a UI in this manner is a challenging problem (e.g., see ). The present work makes no attempt to solve it. Rather, we abstract the notion of task execution into a data structure that we call a “UI script”. We assume that when a PBD system records a user’s actions, the result is a UI script. And when it’s time for a PBD system to mimic a user’s actions back to the UI, it does so by reading and executing a UI script.
Since all of the IA’s interactions with the UI are via a UI script, we can define the IA problem independently of the problem of reliably interacting with the UI. In particular, we define the IA problem as predicting a UI script from a command.  studied a special case of this problem where the natural language input explicitly referred to every user action in the UI script.  and others have studied a related but different problem where the goal was to predict programs from program traces. IAs that aim to learn branching programs must predict branching UI scripts but, in the present work, we limit our attention to non-branching programs and non-branching UI scripts.
Given sufficient training data, it might be possible to solve the IA problem via machine techniques (e.g., ). We are not aware of any pre-existing training data for this problem. To compensate for the lack of data, we used a model with very strong biases, so that it can be learned from only one example (per task) of the kind that we might reasonably expect a non-technical end-user to provide. The Helpa model has three parts for every task :
The class of commands that pertain to . We shall encode in a data structure called a “command template”.
The class of UI scripts for . We shall encode as a non-branching program.
A mapping of variables between and , which we call a “variable binding function.”
We shall now expand on each of these concepts.
A natural language command given to an IA can be segmented into constants and variable values. Variable values are words or phrases that are likely to vary among commands from the same class. Constants are “filler” language that is likely to remain the same for every command in the class. For example, suppose a user wants to train her system to check flight arrival times using the command “When does KLM flight 213 land?” In this command, “KLM” and “213” are variable values. The other symbols are constants. A command template can be derived from a command by replacing each variable value with the name of a variable. “When does flight land?” is a command template for the previous example.
To justify our use of the term “program”, we must first say more about UI scripts. In the present work, we limit our attention to UIs that consist of discrete elements, where all user actions are unambiguously separate from each other and happen one at a time666A smart-phone touchscreen or a web browser would fit this description, for example, but a motion-capture suit would not.. A non-branching UI script for such a UI is a sequence of actions, where every action pertains to at most one element of the UI. E.g., a UI script for a web browser might involve an action pertaining to the 4th text field currently displayed and an action pertaining to the leftmost pull-down menu. A common action that does not pertain to a specific UI element is to wait for some condition to occur in the UI, such as waiting for a web page to load. Besides identifying an element in the UI, each action can also specify a parameter value, such as what to type into the text field or how long to wait for the page to load777More generally, each action can have multiple parameter values. We omit this generalization for simplicity of exposition.. An example of a UI script is in Figure 1.
|action type||UI element||parameter value|
Every non-branching program is also just a sequence of actions. A program differs from a UI script only in that some of the parameter values can be variables. E.g., to create a program from the UI script in Figure 1, we would replace the parameter value “KLM” with a variable name like and the parameter value “213” with another variable name like . Replacing values with variable names, both in commands and in UI scripts, is a form of generalization. This kind of generalization is the most common way for PBD systems to learn (e.g., ).
Finally, a variable binding function maps the variables in a command template to the variables in a program. Helpa allows a command template variable to map to multiple program variables, but not vice versa. The one-to-many mapping can be useful, e.g., when a web form asks for a shipping address separately from a billing address, and the user always wants to use the same address for both. We do not allow multiple command template variables to map to the same program variable. Doing so would merely increase system complexity without any benefits.
3.2 System Architecture and Components
With the Helpa model in mind, we can describe how Helpa works. It has two modes of operation: learning and execution, illustrated in Figures 2 and 3, respectively. In both figures, dashed lines delimit the Helpa system boundary, and numbers indicate the order of events. Both modes use a database of tasks, where every record consists of a command template, a program, and a variable binding function. Tasks are created in learning mode and executed in execution mode.
The user initiates the learning mode by starting the UI recorder (1). The user then provides an example command (2) and demonstrates how to execute the command (3a). During the demo, the recorder is transparent to the user and to the UI. It records all user actions and any relevant responses from the UI (3b). When the user stops the recorder (4), the recorder writes a UI script (5). Then, the learner takes the example command and the UI script (6), and infers a command template, a program, and a variable binding function for the task (7). The command template is shown to the user for approval (8). If the user approves, then the program and variable binding function are stored in the task database, keyed on the command template (9). Otherwise, the user can start over.
Execution mode starts when the user provides a new command (1) without starting the UI recorder. The matcher queries the task database (2) and selects the task whose command template matches the new command (3). The command template for that task is compared to the new command (4), in order to infer the variable values (5). Currently, the values are inferred merely by deleting the constant parts of the command template from the command. Once found, the values are substituted into the program via the variable binding function (6) to create a new UI script (7). The UI script is sent to the player (8), which mimics the way that a user would execute that task in the UI (9). Thus, after learning a new task, and storing it keyed on its command template, Helpa can execute new commands matching that template, with previously unseen parameter values.
We shall now say more about some of the subsystems that our diagrams refer to. The diagrams show the player and recorder outside of the Helpa system boundary, because we do not consider these components to be part of Helpa. A different player and recorder are necessary for every type of UI. However, regardless of the UI, Helpa interacts with the world only through UI scripts. Therefore, Helpa is UI-independent, which also makes it device-independent.
In execution mode, the matcher looks for a command template that can be made identical to the command by substituting the template’s variables with some of the command’s substrings. E.g., the template “When does flight land?” can be made identical to the command “When does United flight 555 land?” by substituting with “United” and with “555”. This kind of matching is a special case of unification, for which efficient algorithms exist .
Figure 3 shows only what happens if exactly one unifying template is found. Otherwise, control passes to a clarification subsystem, which is not shown in the diagram. If no suitable template is found, this subsystem provides a list of available command templates to the user, in order of string similarity to the command, and offers the user a chance to try another command. If multiple templates unify with the new command, they are displayed in order of their amount of overlapping filler text, and the user is asked to disambiguate their command by rewording it.
The learner used in learning mode is responsible for generalizing the command to a command template, generalizing the UI script to a program, and deciding which variables in the command template correspond to which variables in the program. A key insight that makes it possible to learn from only one example is that, typically, each variable value in the example command is the same as a parameter value in the UI script. In contrast, the constant parts of the command typically bear no resemblance to the rest of the UI script.
Helpa’s learner uses this insight as shown in Algorithm 1. The first loop (lines 2–6) matches the parameter values in the UI script with substrings of the command, and stores them in list . After the loop, the list is sorted on the length of the matching substring, in order to give preference to longer matches. The second loop (lines 9–12) traverses in order from longest match to shortest. Each matching action attempts to reserve its substring of the command by filling the corresponding span of the reservation array with its action index . The reservation attempt succeeds if one of two conditions holds: either that span is not yet reserved by any other action, or exactly that span is reserved by another action (i.e. with the same span boundaries). The latter condition enables one command variable to map to multiple UI script variables, but only if it’s exactly the same command variable. Overlapping or nested command variables are not allowed. The successful reservations are stored in list . In line 13, is sorted on the left boundary of the span of the variable value in the command. This order is necessary because, in execution mode, the variable substitution process assumes that the order of variables in the variable binding function is the same as the order of variables in the command template. The last loop (lines 17-20) traverses , whose every element is a mapping from a span of the command to a line of the UI script. The learner creates variable names , where refers to the left boundary of a span of a command variable. The learner uses these variable names to create a command template out of the input command and a program out of the input UI script. Naming the variables in this manner allows one command variable to map to multiple UI script variables. Since line 10 disallowed overlapping or nested command variables, there can be no ambiguity about which command variable each refers to. The last step in the last loop adds each mapping to the variable binding function.
At the present stage of development, Helpa has some significant limitations. Perhaps the most striking limitation, from a user’s point of view, is that Helpa knows nothing about paraphrasing. Helpa doesn’t even know that “April 4, 2016” is the same as “04/04/16”. Likewise, knowing how to execute “Find X” doesn’t help Helpa to execute “Search for X”. In order for the learner to work, the variable values in the command must be identical to the values in the UI script. 888This limitation is not so severe when Helpa is executing a task for the same user who trained it on that task, because that user will often remember the phrasing that they used. The literature offers a variety of techniques for overcoming this limitation. For example, we could use statistical paraphrase generation  to proactively expand a newly inferred command template into a set of possible paraphrases, and store them all in the task database linked to the same task. However, the usability study in the next section was done without the benefit of such techniques.
A more subtle limitation is due to Helpa’s simplistic method for deducing variable values at execution time. The “string difference” method fails when two variables are adjacent in the command template, because Helpa doesn’t know how to partition the adjacent values. E.g., in a command like “I need a Ford Taurus Tuesday,” Helpa has no way to determine whether “Taurus” should be part of the value for the car variable or part of the value for the day variable. Again, there are various natural language processing (NLP) techniques that can solve most of this problem (e.g.,). For now, Helpa works only for commands that have no adjacent variables.
Although it’s easy to think of commands that violate this
constraint, they are relatively rare in practice, at least
in English. We found long lists of English commands for
microsoft-voice-commands-video, and for GoogleNow111111forum.xda-developers.com/showthread.php?t=1961636. Two variables were adjacent in only 5 out of 236 Siri commands, in only 3 out of 91 Cortana commands, and in only 1 out of 98 GoogleNow commands.
4 Usability Study
Our working hypothesis in building Helpa was that, in the vast majority of cases, learning to predict non-branching programs from natural language commands requires no domain knowledge and only the most rudimentary NLP. Our usability study was designed to test this hypothesis, in terms of Helpa’s task completion rates for users who were not involved in Helpa’s development. We also wanted to measure how long it takes users to teach new tasks to Helpa.
4.1 Design of the Study
Since BRAP works only with web browsers, our entire study was done in a Google Chrome web browser, on an Apple MacBook Air computer, through a keyboard and touchpad. Also, due to BRAP’s limitations, we were forced to limit our study to websites that used only simple HTML web forms. So, we could not use a random sample of web sites, or allow our study subjects to choose them.
|1||mortgage calculator||calculator.com/pantaserv/ mortgage.calc||You are a real estate agent, checking whether your customers can afford certain properties.||11|
|2||thesaurus||collinsdictionary.com/english-thesaurus||You are a writer looking for alternative ways to express yourself.||4|
|3||book store||abebooks.com/servlet/ SearchEntry||You are a book dealer serving many kinds of readers.||26|
|4||recruiting||indeed.com/resumes/ advanced||You work for a recruiting firm, searching for candidates to fill various job openings.||14|
|5||investment research||nasdaq.com||You are an investor who likes to frequently check the prices of your stocks.||2|
|6||scientific database||citeseerx.ist.psu.edu/ advanced_search||You are doing a literature search for a research project.||13|
|7||car rental||priceline.com/l/rental/cars.htm||You are a travel agent, researching rental cars.||7|
|8||cooking recipes||allrecipes.com/Search/ Default.aspx?qt=a||You are in charge of selecting new dishes to put on a restaurant’s menu.||26|
|9||airline||united.com/web/ en-US/apps/ booking/flight/ searchOW.aspx||You are a travel agent, checking availability of one-way flights for customers.||40|
|10||dept. store||jcpenney.com||You are shopping for gifts for your friends.||2|
After searching for many hours, we found a sufficiently simple website in each of 10 diverse categories. For each of these 10 websites, we picked a scenario for which an IA with variables might be useful. Table 2 lists the types of sites we used, along with the URL, the scenario we picked for each site, and the number of BRAP-compatible UI elements on the first web page that the study subjects saw. This study design limited each task to use only one website, even though Helpa has no such limitation. Nothing in the Helpa system was tailored to these websites, these scenarios, or this study.
We recruited 10 study subjects, and gave them the instructions in Appendix A. These instructions were designed to help them get around Helpa’s and BRAP’s counter-intuitive limitations. To summarize, subjects were instructed that
variable values must appear in the example command exactly the same way as they appear in the web form;
variables in commands cannot be adjacent; and
task demos must use only the HTML elements that BRAP can record.
subjects must ignore default values that appear in web forms.131313BRAP can read default values in web forms, but we have not yet figured out a way to determine, without explicit indication from the user, whether a given default should become a program variable.
We could not think of a way to explain these limitations without referring to programming concepts. For this reason, we recruited study subjects from among our colleagues, all of whom were experienced programmers.
Each subject began by reading the instructions, and asking any questions they had. Then, an automated script initialized the task database to empty, randomized the order of the websites, and guided the subject through the following protocol for each website:
Subject reads the scenario description (Column 4 in Table 2), and familiarizes themselves with the website.
Subject thinks of a task that is relevant to that scenario, and of a natural language command that is suitable for that task.
Subject interacts with Helpa’s learning mode.
If the subject disapproves of the command template that Helpa generated, return to step 1.
Subject thinks of another command from the same class.
Subject interacts with Helpa’s execution mode.
Subject provides their opinion on whether Helpa executed the new command correctly.
The script recorded and timestamped all of the interactions between Helpa, the study subjects, and the UI.
Table 3 shows the statistics that we gathered from our study. Column A shows the fraction of attempts in which Helpa correctly executed the new command. Despite the current limitations of Helpa and BRAP, the median success rate over all 10 websites was 85%. There were only two kinds of failures. 56% of the failures (about 8% of all attempts) occurred when a web site did something unexpected that BRAP could not handle. For example, in the middle of our study, allrecipes.com started presenting a new kind of pop-up ad, which often prevented BRAP from playing a UI script to completion. The other 44% of failures (about 7% of all attempts) occurred when a study subject failed to follow the instructions. The instruction that users failed to follow the most often was the one pertaining to the limitations of BRAP. An interesting case study here is the department store website jcpenney.com. Subjects had far more trouble with this site than with any other. That’s because its first page was very simple, with just one search box, but its second page had a bewildering array of options for narrowing down the search results. Most subjects excitedly attempted to use one or more of these options. Unfortunately, most of the options were rendered by elements that were incompatible with BRAP, and many subjects forgot about that restriction. Overall, less than 2% of all attempts failed for reasons unrelated to BRAP. These results support the working hypothesis stated at the beginning of Section 4.
The remaining statistics in Table 3 are averaged over only the successfully completed trials. Column B shows the median number of actions per UI script. This number includes the initial actions of navigating to the website and waiting for it to load (as in Figure 1). Column C shows the maximum number of page loads per UI script, again including the initial loading of the website. Only two pages were used on most websites, because most of the websites had no BRAP-compatible elements on the second page. Column D shows the median number of variables per UI script. Column E shows the median number of words per command, after tokenization. We used a generic English tokenizer, which merely separated words from punctuation.
Column F of Table 3 shows the median number of seconds that it took a user to interact with Helpa’s learning mode for the given website. Time was measured by the wall clock and includes network delays. We found that most users struggled with Helpa a bit until they understood that it won’t work unless they follow the instructions very precisely. So we also report the median user effort after acclimation, in Column G. This measure is the median time per demo for each website, excluding users for whom that website was the first or second that they worked on.141414Tables 2 and 1 are both sorted on the measure in Column G. Our results show that users can usually teach Helpa a new task in less than a minute (), often much less. Thus, despite its current limitations, Helpa represents a major advance on the user effort criterion: We are not aware of any other IA that can learn to predict programs with variables from natural language commands nearly as quickly.
Appendix B shows some of the more interesting examples of the variability of command templates for some of the websites in our study.
Virtual assistants (VAs) have become very popular, but not nearly as popular as they could be. We conjecture that one of the main reasons for their slow adoption is that users cannot customize them. Our instructible agent (IA) Helpa offers users a way to customize their VAs, not only in terms of which tasks the VA can perform, but also in terms of the commands used to trigger those tasks, and the way the tasks are executed. To encourage research on this topic, we are sharing the data set that grew out of our usability study.
Since Helpa succeeded for most users on most websites, we claim that Helpa can learn many unrelated tasks without its creators’ involvement. Since Helpa uses no domain-specific knowledge of any kind, we claim that it has almost complete coverage of tasks that can be represented by non-branching programs. We don’t know of any other IA that can learn programs with variables in arbitrary domains without its creators’ involvement. We also don’t know of any other IA that can be taught new tasks with variables in less than a minute per task.
The work presented here provides a springboard for several directions of future research. An obvious direction is to improve Helpa’s components to reduce or remove its limitations. Another direction is to develop learning algorithms that can use the available data more effectively, or learning algorithms for branching programs. Yet another direction is to deploy a speech-enabled Helpa on a massive scale, gather a much larger number of examples, and work towards a future where Helpa can execute a user’s new task correctly without any training, because it has already learned how to do so from other users.
Appendix A: Instructions Given to Study Subjects
Thank you for agreeing to participate in our Helpa experiments! Helpa is a virtual assistant (VA). Like other VAs, it can execute verbal commands through a suitably instrumented agent, such as a smart-phone or a web browser. What makes Helpa different from other VAs is that you can teach it new tasks without any programming. We are studying how people use this feature, in order to make it easier to use. We are aiming to make the training procedure so fast and intuitive that it becomes a significant time-saver for developers of VA apps, and eventually also for end-users.
Our main innovation is the way that Helpa is trained. To teach Helpa a new task, you need only give it an example command and demonstrate how to execute that command. Helpa can then figure out how to execute new commands of that type. With a bit of practice, we have been able to teach Helpa some new tasks in less than a minute each!
We are starting with relatively simple tasks that involve no loops or conditionals. There are many such simple tasks that people perform often enough to justify automation. The current set of experiments will focus on the common example of filling out forms online.
For example, suppose a user wants to fill out a form on a travel
website, and gives the command “Find a hotel for 2 nights starting
August 3, 2015.” A developer who is trying to program a VA to
execute such a command would partition it as follows:
Each yellow segment is a variable that needs to be mapped to a field on the web form. The blue segments are contextual “filler”, which a given user is likely to say in a similar way every time they want this kind of task done. Without Helpa, a developer would have to specify the segmentation explicitly. Helpa can figure out the segmentation and variable mapping, so that it can be taught by a user who does not have access to its source code.
We believe the Helpa paradigm can work on any device, but our current experiments will be done only in a web browser. Also, eventually, people will interact with Helpa by speaking to it. For now, all interaction is through a text-only “control” window.
The success of our experiment depends on your careful adherence to the instructions. So please read them very carefully, and tell the experimenter if there is even a single word that is not perfectly clear.
To teach Helpa a new task, you must give it an example command, and a demonstration of how to execute that command in a web browser. The experiment will ask you to do so on 10 websites with varying levels of complexity. You do no need to use all or even most of every website. Try to interact with each website the way you imagine a typical non-technical user might. Remember that this is a usability study, not an acid test of Helpa’s robustness. After you teach Helpa a new task, you will test it on that task, and decide whether it learned the task correctly.
The current experiments are designed to study whether Helpa can correctly learn to execute simple commands, as well as to study how users interact with it. For this purpose, we have built only a rough prototype of Helpa, which has many limitations. In the future, we plan to improve Helpa by removing most of these limitations. For now, keeping in mind the example command segmentation above, please pay careful attention to the following:
Helpa is currently focused on tasks that involve filling out web forms. Therefore, every variable in your commands must correspond either to a text field or to an option in a pull-down menu. Your demos can also use check-boxes, radio buttons, and push-buttons (like “Submit” or “Search”) but these elements cannot represent command variables. Your demos cannot involve any other type of web page elements, such as hyperlinks, tabs, sliders, maps, calendars, etc.. Your demos cannot use the Enter key to signal form completion. Also, Helpa cannot handle pop-up menus or any other kind of pop-up. In particular, menus that appear for automatic completion of text fields should not be used.
The variable instantiations must appear in the example command exactly the same way as they appear in the web form. E.g., if the web form displays dates like “August 3, 2014”, the example command cannot refer to “08/03/2014” or even to “August 3 2014”.
Ignore default values. If your demo needs to use a web form element that appears with the correct value already in it, enter the value anyway, as if it wasn’t there.
The variables in a command cannot be adjacent. They must be separated by some filler. E.g., you can’t use a command like “Find a 2014 Porsche for rent” where “2014” and “Porsche” refer to the different fields of a web form. However, you could rephrase such a command as “Find a Porsche from 2014 for rent” so that the filler “from” separates the two variables.
No web form element may be a composite of two or more command variables, or vice versa. E.g., if there are separate pull-down menus for the month and the day of the month, the command cannot combine them in the same variable such as “August 3”. Or if there is a menu option like “price range from $100 to $200”, the command cannot have separate variables for the min and the max.
(for training only) No variable value can appear in the command more than once, either as another variable value or as part of the contextual filler. E.g., you cannot use commands like “Find a hotel for 2 nights for 2 people…” or “Find a synonym for the word find.”
Also, Helpa is currently a bit slow. To avoid confusing it, please pay careful attention to the prompts in the control window, and don’t touch the browser until it finishes loading and the control window says to go ahead. This is important every time the browser loads a new page, which can be triggered unexpectedly in many ways, sometimes as simple as clicking a radio button.
Frequently Asked Questions
Is there a limit on the number of variables in a command?
No, there is no limit. However, as previously mentioned, this is a usability study, not an acid test. So please don’t make your commands more complicated than they would be for a typical non-technical user.
Can a demo involve more than one web page?
Yes. However, remember that you cannot click on hyperlinks, so the only way to get to another web page during your demo is by clicking a button such as “Submit” or “Search”. If there are suitable web page elements on the next page, then you can continue your demo there.
You should have a printed copy of these instructions handy during the experiment, so that you can refer to them whenever you have any doubts.
Feel free to ask the experimenter any questions that you might have. When you think you understand the instructions well enough to start, press ENTER in the control window.
Appendix B: Examples of Command Templates
Here are some examples of command templates that Helpa inferred in learning mode during our usability study. Underscores represent free variables.
search for ___ . dictionary ___ what is a synonym for " ___ " ? what is another word for ___ ? search collins for ___
search for ___ as the exact phrase and ___ of work experience and a ___ degree in the state of ___ . i ’ m looking to hire a ___ student in ___ with ___ experience find resumes of people with at least one of ___ and ___ experience in ___ find ___ candidates with experience in " ___ " who worked at ___ find me resumes with the kword ___ and last job title ___ and one job titled ___ with ___ experience with a ___ degree located in ___ find job candidates who did ___ work in ___ find ___ grads in ___
search for ___ current stock quote for ___ show ___ performance for 1m period what is the value of ___ stock
search for ___ in the text field with ___ in the keywords field for publications between the year ___ and ___ sorted by citations . search for publications by ___ about ___ find papers by ___ from ___ to ___ find articles by ___ about ___
search for ___ as pick - up with ___ as pick - up date at ___ and ___ as drop - off date at ___ . find me a car at ___ airport pickup ___ and drop off ___ show cars at ___ at ___ on ___ i need to rent a car from ___ on ___ at ___ until ___ at ___
search for ___ with prep time ___ and meal is ___ and " with these ingredients : " is ___ and ___ for " but not these ingredients : " . i want to make a ___ with main ingredient ___ with ___
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