Control tasks
Control tasks contain samples of correct responses. They allow you to monitor the quality of task completion without having to check all the responses. Control tasks simplify the verification process, help identify performers' qualifications, and save your time.
When to use
Use control tasks to assign a skill to performers based on their responses and ban performers who submit incorrect responses.
- Don't use it if:
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- You have a lot of response options.
- Users need to attach a file to their assignment.
- Users need to transcribe text.
- Users need to select objects in a photo.
- Tasks don't have a correct or incorrect response. For example: “Which image do you like best?” or “Choose the page design option that you like best”.
Rule settings
The If and then fields in this rule are mandatory. If you don't fill in at least one field, you won't be able to save the rule.
| Field | Overview |
|---|---|
| Recent values to use | The number of the performer's last responses to control tasks. To calculate control task responses from all project pools, fill in the field in the rule for each pool. If this field is not filled in, the calculation includes responses in control tasks only in the pool to which the rule applies. |
| If | A condition for performing the action in the then field:
To add multiple conditions, click |
| then | Action to perform for the condition:
|
.| Field | Overview |
|---|---|
| Recent values to use | The number of the performer's last responses to control tasks. To calculate control task responses from all project pools, fill in the field in the rule for each pool. If this field is not filled in, the calculation includes responses in control tasks only in the pool to which the rule applies. |
| If | A condition for performing the action in the then field:
To add multiple conditions, click |
| then | Action to perform for the condition:
|
Examples of rules
Purpose: filter out performers who often make mistakes.
Solutions:
- Ban performers based on control tasks and the percentage of correct responses
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Both rules work independently:
- If the performer gives at least 3 responses to the control tasks, the percentage of correct answers is assigned as the skill value. This is useful if you want to prevent performers with a low skill level from completing your tasks.
- If the performer gives at least 3 responses to the control tasks and the percentage of correct answers is less than 60%, they lose access to the project.
The calculation uses up to 10 of the performer's recent responses to the project's control tasks.
The performer is banned after the first incorrect response to the first, second or third control task. The skill is not assigned. Since the ban reason is not specified, there is no way to find out why the performer is banned.
All rules are applied independently:- If the performer gives at least 3 responses to the control and training tasks, the percentage of correct answers is assigned as the skill value.
- If the performer gives 2 incorrect answers to 3 control tasks, they lose access to the pool for 10 days.
- If the performer gives 2 incorrect responses to 4 control tasks, they lose access to the pool for 10 days.
- If the performer gives 5 or more responses to the control tasks and the percentage of correct responses is less than 80%, they lose access to the pool for 10 days.
A set of rules like this prevents performers from being banned for one incorrect response and lets you maintain high accuracy.
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Skills help identify how well performers do your tasks. You can ban performers with low skill levels from completing tasks in your pool or project.
If the performer completes 3 control or training tasks, they get a skill. Use the skill value to set access to other pools with filters.
Example of filter settings
This rule will never take effect because the number of responses counted (Recent values to use) is less than the number of responses in the rule (number of control responses).
- Ban performers if their percentage of correct responses to control tasks is less than 40%
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If the percentage of correct responses in the control tasks is less than 40%, the performer loses access to the project for 30 days.
This rule doesn't take into account responses in the training tasks for banning.
If the percentage of correct responses in the control tasks is less than 40%, the performer loses access to the project for 30 days. The rule will be applied once — after the fifth response in the control task.
Troubleshooting
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.
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.
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.
The tasks themselves are not exported, only the project configuration and the settings of the selected pool. You can download the completed tasks from the pool in the Sandbox and import them to the exported pool.
To download only the control tasks (if you completed them in the interface), go to Mark up, then click Control tasks and Download.
You can upload your main and control tasks separately using different files.
If the user already got paid for the tasks, the money can't be refunded to you.
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.
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.