# Setting up a pool

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## Filters

Can I select Tolokers from a specific city of residence or is the only option “Region by IP”?

Yes, you can do that. In the filters, select Profile → City. Please note that the profile data is entered by the Toloker when they register in Toloka. We recommended that you use the filters Region by phone number and Region by IP.

Can I use a skill beyond a particular pool or project and apply it to other projects as well?

Yes, of course — you can use the same skill for different projects. But most often, a skill is intended for a specific project. If the Toloker completes a certain task well, this doesn't mean that they will complete other ones successfully. Another disadvantage is that if you filter by skills that were set long ago, you will artificially limit the number of available Tolokers.

I want to calculate a skill based on performance in multiple projects. Is that possible? If it is, can I use “Aggregation by skill”?

If you mean multiple different projects, you can't do that.

You can merge all the projects into one and use History size in the quality control rules. See examples in the Control tasks post.

You can use Aggregation by skill, but you'll need to list all the possible values, which is probably not the best choice. Perhaps you'll find another method of aggregation helpful.

I created a project and a pool, but the Next button doesn't work or the preview shows a blank screen.

Toloka lets you know that something is wrong with the project. The blank screen often appears when there are errors in the task interface, including the JavaScript code. The Next button may be disabled if the output specification lacks some field or contains invalid values, or if, for example, you configured validation for a nonexistent field in JavaScript.

Are there any easy ways to assign a certain user a skill in Toloka, even if the Toloker didn't do any tasks (like I can do in the Sandbox)?

In the main Toloka version, you can only assign a skill to Tolokers who have completed at least one of your tasks. There is no option to assign a skill to an arbitrary user. To limit the audience of users who will see your project, use filters. For example, specify the city, date of birth, gender, or some other parameters of your target Tolokers.

Can I somehow limit the number of Tolokers that can take tasks from the pool at the same time?

Tasks from an open pool are available to every Toloker that matches your pool filters. You can restrict access, like by using a skill.

The Tolokers completed training for the first pool and got the skill. A week later, we cloned the pool, but all the Tolokers lost their skill. Which parameter affects skill expiration? Do all the Tolokers need to complete the training again?

The validity period of the training skills is controlled by the Retry after parameter. The skill is deleted after a period specified in days in the Retry after field, if the Toloker:

• Has a skill value lower than the one specified in the Level required field.

• Didn't complete any tasks linked to training during this period.

Your Tolokers will need to be trained again.

Why is my project not available in the mobile version of Toloka?

Tasks in pools are automatically available in the web version of Toloka and the mobile app. Check the pool settings. You might have the Client = Toloka web versionfilter on.

Can I add an arbitrary user as a Toloker?

If the user mismatches your preset filter, they can't see the task. You can only remove the restricting filter from the pool. You can test the task in the Sandbox by adding the desired user to your trusted list.

Can I set up a task to display it to users with certain demographic and geo parameters? For example, “US only, 30–45 years old”.

You can do that. To select Tolokers for the pool, use filters.

How do I make the task available not only from desktops, but also from mobile devices?

Tasks in pools are automatically available in the web version of Toloka and the mobile app. Check the pool settings. You might have the Client = Mobile Tolokafilter on.

Can I select specific Tolokers for my tasks because I liked their results in my previous pools?

You can assign a skill to these Tolokers based on their performance in the previous pools. Use this skill as a filter in the new pool.

How do I set up a filter so that the pool is available to Tolokers who don't have a specific skill (like a “spammer”)?

Specify this skill as a filter, but leave the value field empty (this is equivalent to absence of the skill).

How can I raise the skill value for a Toloker, if they already have the skill?

If the Toloker already has a given skill, you can't add the same skill to them from the task review interface. You can open the Toloker's profile and edit the skill value.

Can Tolokers see that they were assigned a skill?

If it's a public or training skill, they see it and they get a message about it.

Can I show a skill in the task interface?

There is no such option. If the skill is public, the Toloker sees it in their profile.

Why can't I find the Toloker's gender in the Toloker data, although I can filter people by this attribute in the pool settings?

Requesters can't see the full details about specific Tolokers. So you can't see information like the date of birth, gender, last name, or first name. However, you can use filters by date of birth and gender (in the pool settings). This way you can select a group of Tolokers without accessing the personal information of individual Tolokers. This decreases the risk of user de-anonymization.

How do I automatically assign skills based on Toloker responses to my questions?

You can do that using the Control tasks rule.

1. Upload the task file using Smart mixing.

2. Specify student as the correct answer to the question. Don't take other questions into account (leave the fields empty or unselected).

3. Add the Control tasks rule to the pool: if the percentage of correct control answers = 100, then set the skill value Student = 1.

See the screenshot

Other questions

## Quality control

How do I set quality control in a pool correctly?

The settings for quality control rules depend on the type of tasks. General recommendations:

• Always use one or more ways to control quality of answers.

• Counting fast responses makes sense for most tasks.

• If the Toloker has to choose between options (for example, by selecting checkboxes), check the answers using majority vote or control tasks.

• If the Toloker has to provide a response as a text or link or upload a photo, the best way to control quality is by reviewing assignments. You can outsource task acceptance to Tolokers. Create a task with a question (for example, “Is this phrase translated correctly?”) and possible responses (for example, “yes”/“no”). Set up overlap and majority vote check.

• If a task is more like an opinion poll (for example, choosing nice pictures from a set), majority vote is not a good way to control quality. Make control tasks with artificial examples where the choice is evident.

How many control tasks do I need to add?

We recommend adding at least 1% of control tasks in the pool. And for small pools — 5–10%.

Why's that?

Each control task is shown to the Toloker only once. If you use smart mixing, you determine how many control tasks should be in a suite. If each suite contains one control task, then the maximum number of suites the Toloker can complete is equal to the number of control tasks in the pool. If you increase the number of control tasks in a suite, the number of suites available to the Toloker decreases by the same number.

There shouldn't be too few pages available. Otherwise:

• You won't be able to correctly evaluate the quality of the Toloker's responses.

• The Toloker won't be interested in completing such tasks because they'll spend a lot of time studying instructions but won't earn much.

Example

#### A large pool with 1% of control tasks (good)

There are 10,000 tasks in the pool, and 100 of them are control tasks (1%). Each suite contains 10 tasks, and 1 of them is a control task. Hence, a user can complete up to 100 suites.

#### A small pool with 1% control tasks (bad)

There are 100 tasks in the pool, and 1 of them is a control task (1%). Each suite contains 10 tasks, and 1 of them is a control task. Hence, each user can only complete 1 suite.

#### A small pool with 10% control tasks (good)

There are 100 tasks in the pool, and 10 of them are control tasks (10%). Each suite contains 10 tasks, and 1 of them is a control task. Hence, each user can complete up to 100 suites

If there are few control tasks in the open pool, add new control tasks.

What for

In a large pool with few control tasks, a situation might occur when users who have completed a lot of tasks in the project stop getting new task suites. This happens when the Toloker completes all control tasks in the pool.

Note

To filter out Tolokers, use the Control tasks quality control rule. To rank Tolokers by the quality of responses in control tasks, use a skill.

How do I add new control tasks to an open pool?

To make new task suites available to all users, including those who have already completed tasks in this pool:

1. Stop the pool.

2. Upload the file with new control tasks.

3. Start the pool.

For open pools, we don't recommend creating control tasks from other types of tasks that have already been completed. This is because users who have already given their responses to them won't be able to re-complete such tasks as control tasks. In order for these users to continue completing task suites, the control tasks in the pool must be new.

How are the correct responses to control questions counted?

The Control tasks rule starts working after the Toloker completes the number of control tasks you specified. If your pool contains both training and control tasks, you can take into account the responses in both of them (the Number of responses parameter) or only in control tasks (the Number of control responses parameter).

As soon as the needed number of responses is collected, Toloka calculates the percentage of correct and incorrect responses and performs an action (assigns a skill, or blocks the Toloker in the pool or in the project). Then this percentage is updated as the tasks are completed by the Toloker. The number of the Toloker's recent responses that's used in the calculation is set in the Recent control task responses to use field. If you leave it empty, all the responses from the Toloker in the pool are counted.

Should I create a skill for every pool?

It is better to use one skill in a project. You can choose the way to calculate the skill:

• Calculate the skill for each pool separately. The current skill value is the value of the skill in the pool the Toloker completed last. This option is convenient if:

• The pools are intended for different groups of Tolokers (for example, there are filters by city or country).

• Pools are started one by one and you don't want to take into account the responses in the previous pools to calculate the skill in the current pool.

This calculation method is used by default when adding a quality control rule to a pool. For the control tasks block, leave the Recent control task responses to use field empty.

• Calculate skill based on all tasks in a project This option is good if the pools are small and you don't need to have skill calculated for each pool.

This option is available only for skills on control tasks. To use it, fill in the Recent control task responses to use field in pool quality control rules.

Can I make my training or control tasks totally different from the general tasks?

Your training and control tasks have the same project specification. However, you can create a separate project with the tasks and assign a skill based on user responses. Then you can admit Tolokers to the main project based on their skill.

Isn't the exam a regular pool that I pay for? How does it differ from a regular pool?

An exam pool contains only control tasks. It's usually small and used for checking how well users learned to do your tasks after they read the instructions and completed the training. Unlike your main pool, you already know the correct responses for every task in this pool. You can set the price to zero.

Based on the results of responses to control tasks, you can assign a skill to the Tolokers and then specify it in the main pool as a filter. For example, MySkill = 80 or = Is missing. You don't have to create an exam. For simple tasks, the training pool provides enough practice, but many requesters also use exams.

Is the time specified per task suite in the fast response settings?

Yes, the fast response settings specify the time per task suite.

I set up quality control, then I copied my user requirements. All my quality control settings were deleted and replaced with the copied settings. Is that normal?

Yes. When you copy the filter and quality control settings, the settings you previously added manually are overwritten. You should see a warning about this in the copy settings window.

The pool has an overlap and majority vote set up, but some fraudulent user opens the task suites, does nothing, and submits empty assignments. Could this cheater get more tasks from the pool before the results of other Tolokers are known? Could a user quickly click through a lot of task suites before the majority vote is accumulated to ban the cheater?

Yes, unfortunately, this can happen. This is why we recommend that you offer a training task or exam before the general task. In this case, only those people who showed good performance at the previous stage are selected for the main pool.

How do I set up an exam so that different people can take it without running out of tasks?

When you load tasks, use smart mixing. In this case, you'll have infinite overlap in your exam.

However, this poses the risk that you might spend a lot of money on the exam. You might want to open this pool only when the main pool opens, and close it when labeling of the main pool ends.

How do I test users to determine which kinds of tasks they do better and assign them relevant tasks?

You can add a training pool to test your Tolokers. Based on the test results, assign skills to the Tolokers for the tasks they do best.

Then open your pools only to the Tolokers that have a certain skill: use filters for this.

If I upload tasks using smart mixing, does it mean that the same file should contain both the control tasks and general tasks, or can I upload them separately?

Smart mixing is set up when you upload tasks to the pool. After creating a pool, click Upload and select the method for generating task suites. You can upload them using separate files or one file, arranging them in any order.

If a cheating Toloker gives a lot of incorrect responses, and the system eventually bans them for errors in control tasks, do I have to pay for the bad responses anyway?

If the Toloker already got paid for the tasks, the money can't be refunded to you.

Can one Toloker get access to two pools in the same project? Can I avoid that?

Yes, if they can access both pools, they can do both of them. To restrict access to subsequent tasks for a Toloker, use the Completed tasks rule and select a ban at the project level.

If I ban a Toloker for doing my tasks too fast, will all their responses be deleted and given to other Tolokers for labeling?

No. The responses of these Tolokers aren't automatically excluded from the final results file.

But you can do it yourself if you want. When downloading the results, select the option Exclude assignments by banned users to delete the responses of Tolokers who were banned at the moment of downloading. You can also forward all the assignments from banned users to other Tolokers using the Re-completion of assignments from banned users rule.

Can I create two active training pools, one for practice and the other for admitting users to the main pool? In other words, one pool is for users to practice and the other pool tests them.

Yes, you can do that. In this case, create the first pool based on the training pool and the exam pool based on your main pool. If a pool contains only control and/or training tasks, the price can be set to zero.

In the exam pool, you can create a skill reflecting the exam result and granting admission to the main pool. For example, if the number of responses is ≥ 10, set the skill value in the <exam skill> as % of correct responses. In your exam pool user requirements, specify: <exam skill> < 80 or = Is missing>. In the main pool, set up a filter: <exam skill> >= 80 and (<main skill> >= 70 or = Is missing). You can choose the skill values depending on how well the Tolokers handle your task.

My task uses a form with multiple fields. When there is an overlap and “Majority vote” is used for quality control, is each field taken into account, or if one field mismatches the majority vote, are the task results considered incorrect?

All responses to the task are taken into account. If one response differs from the majority vote, the whole task is counted as mismatching the responses of other Tolokers.

Have I understood correctly that if I use set the the skill value = 1 with the percentage of accepted responses >= 75 and 10 recent values to use, for every 8 correctly completed tasks out of 10 the Toloker is given 1 skill point?

No, this is incorrect. With these settings, each time a rule condition is met, the Toloker gets skill = 1. To change the skill value in the process of task review, you need a “multi-step” rule, which has multiple identical rules with different values of Total reviewed responses.

I created a training pool with one task containing a hint. The Toloker fails to complete the task on the first attempt, but finally succeeds. The Toloker gets the skill 0. How do I grant to the Toloker access to my tasks? The minimum required level that you can set is 10.

Technically, if you have only one task in your training pool, you don't have this option. The skill will be either 0 or 100. We recommend that you add several tasks, or at least 2 so that the Toloker will practice on the first task and will be able to do the second task correctly. In this case, you can admit users to your main pool starting from the skill value of 50.

You can also create a training pool based on the main pool. Assign a skill using the Control tasks rule: in this case, you can admit users with any skill level to your main pool, even if the value is zero. But we don't advise giving tasks to people who failed training.

Can I use manual review in the training pool?

No. But you can create a pool of the Training type based on your main pool and enable manual review there.

Can the Tolokers see which questions are control tasks?

No, they can't.

I have two text versions that I want to show to my respondents: one version to half of the audience, and another version to the other half (like in A/B testing). Is this possible in Toloka, or do I need to create two separate projects?

If you pass texts to the input data, you can load 2 different tasks in the pool. In one task, pass Text 1 in the INPUT: <input field name> field, and in the other task, use this field to pass Text 2. But if the text is in the HTML block of the task template, you need to clone the project. To let a Toloker do only one task in your project, use the Submitted responses rule. You can assign a skill or ban the Toloker after they submit one response.

If I ban users from my project so that everyone can complete a maximum of one task, are the Tolokers notified of the ban?

No, the Tolokers are unaware of the ban.

When I export a project from the Sandbox, the task files are not exported. Is this how it's supposed to work? I suddenly lost the markup of the control tasks that I created in the sandbox.

I want to create an exam with three tasks. If a user does two out of three tasks correctly, they get the skill. So I try to use 3 in the Recent control task responses to use field, but I get an error that the value is too small. Can I get around this without increasing the number of tasks to five?

The Recent control task responses to use field is for the number of recent responses from the Toloker. If you use manual review for your task, then to set up your intended rule you need to specify 3 in Total reviewed responses.

What output format do I use for the review results to filter out mismatching users based on the “Majority vote”?

To perform actions with users (assign a skill or ban them) based on the majority vote, add a relevant rule to the pool.

Don't forget to enable Keep task order in the pool parameters. Majority vote is used in the projects with preset options (radio buttons or checkboxes). This rule won't apply to the text entry or file upload fields.

I want to create training and exam pools to match the entered text against a sample, and sometimes the matching fails. How do I implement this?

For a control or training assignment to be counted as correct, it must exactly match the control assignment. To do this, you need to normalize the response text using JavaScript: remove spaces, punctuation marks, special characters, and capital letters, and write the result in a separate output field. Now you can match the processed assignment text against your control text.

Another option for selecting Tolokers for a project of this type is manual review.

In the section about control questions, does "Number of control responses" mean the total number of responses to control questions (including incorrect responses) or the number of correct responses to my control questions?

This is the total number of responses to the control questions.

How do I classify users as good Tolokers and poor Tolokers as they complete tasks, and ban the poor Tolokers?

You can create a task pool for all your Tolokers and create Toloker skills in it. In this case, you can open your tasks only to the Tolokers with the necessary skills.

Why has the speed of pool completion dropped?

Possible reasons:

• You've stopped the main pool. This could limit the number of Tolokers with access to the pool. Start the training pool again. There will be more Tolokers who can access the tasks.

• The filters you set are too strict. For example, a strong restriction on a certain skill that most users don't have.

• Too many users are banned. Ease the quality control rules.

How can I speed up the pool completion?

Other questions

## Overlap

What overlap should I set?

Overlap defines how many Tolokers complete the same pool task.

The best overlap is an overlap that provides satisfying quality of results. For most tasks that are not reviewed, overlap from “3” to “5” is enough. If the tasks are simple, overlap of “3” is likely to be enough. For tasks that are reviewed, set overlap to “1”.

Can I change overlap after the pool is started?

Yes. Open edit mode for the pool and set a new overlap value. You don't need to restart the pool. Updating the settings is usually fast, but if there are many tasks, it may take several minutes.

With dynamic overlap, is it possible that the pool will close before the tasks for minimal overlap run out? The overlap increased, but the pool is closed, and I need to start it manually.

Yes, this might happen. You must set an adequate pool closing interval.

How does counting work if I set overlap = 3 in the pool and response threshold = 3 in the majority vote?

In this case, if you don't have 3 identical responses for your task (response threshold), no user would be considered a good or poor Toloker, because the system can't see which of the Tolokers made an error.

But if you set response threshold = 2 with overlap = 3, then two users with the same responses are considered good Tolokers, but the third user, who gives a different response, is a poor Toloker.

Can I do it like this: set a basic overlap of 2 users, then, if both Tolokers select the same response, close the pool, but if they give different responses, show the task to one more user?

Yes, you can do that. Set up dynamic overlap (incremental relabeling, IRL).

Is there a cross-check feature for tasks?

You can use overlap to let multiple Tolokers do the same task. The overlap value is set up in the pool settings.

Why is the maximum number of submitted assignments in the progress bar less than the total number of uploaded tasks?

The progress bar shows the number of task suites including the overlap. If the overlap is greater than one, the number of task suites is different from the total number of tasks.

Other questions