Setting up quality control
Quality control lets you get more accurate responses and restrict access to tasks for cheating performers. Quality control consists of rules. All rules work independently.
Quality control rules that you set in the project are applied to all project pools, so you can't change them in one pool.
- Go to the pool editing page
- If you already have a pool with the appropriate quality control settings, you can copy it along with the audience settings. To do this, go to Users filter and click Copy settings from... and then Add Quality Control Rule.
Under Quality Control, choose the rules you want to use.
If you aren't sure what quality control rules you need, select a quality control preset with default settings.- Make settings for the rules you added. Below is a list of rules with links to detailed information about the rule settings.
- Save the pool.
List of rules
- To keep track of how often performers make mistakes:
- Control tasks: Use them to assign a skill to performers based on their responses to control tasks and ban performers who submit incorrect responses.
- Majority vote: Quality is based on matching the response from the majority of performers who complete the same task.
- Results of checking: Evaluate performers based on the number of accepted and rejected responses.
- To protect your project from robots and cheaters:
- Fast responses: Control the minimum time that must be spent per task suite.
- Captcha: Show a captcha from time to time to make sure tasks aren't completed by robots.
- Skipped assignments: Restrict access to your pool tasks for performers who skip multiple assignments in a row.
- To attract a variety of performers:
- Submitted assignments: Limit how many assignments each performer can submit in the pool per day.
- To allow recompletion of certain assignments:
- Recompletion of assignments from banned users: Send completed assignments to other performers to redo them if the performer was banned.
- Processing of rejected and accepted assignments: Send rejected assignments to other performers to redo them.
What's next
- Learn more about how to set up a pool:
- Selective majority vote control.
Troubleshooting
Always use one or more ways to control quality of answers.
Counting fast responses makes sense for most tasks.
If the user has to choose between options (for example, by selecting checkboxes), check the answers using majority vote or control tasks.
If the user 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 performers. 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.
Calculate the skill for each pool separately. The current skill value is the value of the skill in the pool the user completed last. This option is convenient if:
The pools are intended for different groups of performers (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 values 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 values to use field in quality control rules in pools.
- No
- Don't show captchas.
- Low
- Show a captcha after every 20 assignments.
- Average/High
- Show a captcha after every 10 assignments.
- No
- Don't show captchas.
- Low
- Show a captcha after every 20 assignments.
- Average/High
- Show a captcha after every 10 assignments.
You've stopped the main pool. This could limit the number of performers with access to the pool. Start the training pool again. There will be more performers 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.
- To motivate performers, assign a public skill and use dynamic pricing.
- Try to increase the project rating, so that your task is higher in the list of tasks for performers.
- Adjust the quality-speed ratio.
- Set a higher priority for the pool among other project pools.
The settings for quality control rules depend on the type of tasks. General recommendations:
It is better to use one skill in a project. You can choose the way to calculate the skill:
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 performer 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 performers.
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.
Yes, if they can access both pools, they can do both of them. To restrict access to subsequent tasks for a performer, use the Completed tasks rule and select a ban at the project level.
No, this is incorrect. With these settings, each time a rule condition is met, the performer 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.
Yes, the fast response settings specify the time per task suite.
You can add a training pool to test your performers. Based on the test results, assign skills to the users for the tasks they do best.
Then open your pools only to the users that have a certain skill: use filters for this.
This won't lower performer ratings. Even if you ban users from your project based on the testing results, this won't affect their rating.
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 to select performers for this type of projects is non-automatic acceptance.
The Recent values to use field is for the number of recent responses from the performer. If you use non-automatic acceptance for your task, then to set up your intended rule you need to specify 3 in Total reviewed responses.
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 performer do only one task in your project, use the Submitted responses rule. You can assign a skill or ban the performer after they submit one response.
We recommend adding at least 1% of control tasks in the pool. To filter out performers, use the Control tasks quality control rule. To rank performers by the quality of responses in control tasks, use a skill.
The Control tasks rule starts working after the performer 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 user in the pool or in the project). Then this percentage is updated as the tasks are completed by the performer. The number of the performer's last responses used for the calculation is set in the Recent values to use field. If you leave it empty, all the responses from the performer in the pool are counted.
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 performers to the main project based on their skill.
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 users 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.
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.
You can upload your main and control tasks separately using different files.
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 performers handle your task.
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 performer 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.
This is the total number of responses to the control questions.
No. But you can create a pool of the Training type based on your main pool and enable non-automatic acceptance there.
No, they can't.
The tasks themselves are not exported, only the project configuration and the settings of the selected pool. However, you can download your marked up tasks from the Sandbox pool and import them to the pool you created. To download the control tasks only (if you marked them up in the interface), go to Mark up, then click Control tasks and Download.
You can deny access to the pool if the performer's responses are too fast, if they don't match the majority vote, or if the performer makes too many mistakes in control tasks. Tasks completed by such performers can be given to other performers.
Indeed, this rule is probably too strict. Even the most careful user can make a mistake, so you probably want to relax the rule. Besides the requester-specific bans, we have system processes that ban users who regularly fail captcha checks in Toloka.
If the user already got paid for the tasks, the money can't be refunded to you.
No, the users are unaware of the ban.
No. The responses of these performers 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 performers who were banned at the moment of downloading. You can also forward all the assignments from banned users to other performers using the Re-completion of assignments from banned users rule.
You can create a task pool for all your performers and create performer skills in it. In this case, you can open your tasks only to the performers with the necessary skills. This won't affect their rating.
Even if you ban a performer from the project, this won't affect their rating either.
Captcha is usually used in simple projects with automatic acceptance, like classification, categorization, or information search. These are cases where there are few response options and users don't need to upload files or write texts. It helps you filter out bots and sloppy performers.
The percentage of correct responses is based on the total number of captchas processed by the performer within the “range” specified in the Recent values to use field. If the value is empty, the percentage is calculated using all the captchas that are shown for the tasks in the pool which uses the captcha rule.
Yes, unfortunately, this can happen. This is why we recommend that you offer a training task or exam before the main task. In this case, only those people who showed good performance at the previous stage are selected for the main pool.
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 performers.
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.