Aggregation of results

If tasks were issued with an overlap of 2 or higher, run aggregation of results. Toloka will process all Tolokers' responses for the task and issue the resulting response and its confidence level.


If you run the pool with the manual review, make sure that all responses are accepted.

In the interface
Via Toloka API
  1. Open the pool.

  2. Click Drop-down button next to the Download results button.

  3. Choose the aggregation method:

Aggregation takes from several minutes to several hours. Track the progress on the Operations page. When aggregation is complete, download the file with the results.

To receive notifications and emails when results aggregation is completed, set up notifications:

  1. Log in to your account.

  2. Go to Profile → Notifications → Pool or aggregation completed

  3. Choose the notification method:

    • Email: Messages will be sent to your email address.

    • Messages: Notifications will be displayed under Messages in your account. Apart from you, those who set up shared access to your account can see them.

    • Browser: Notifications will be sent to the devices that you logged in to your account from.

Dawid-Skene aggregation model

The Dawid-Skene aggregation model takes into account the heterogeneity of Tolokers when aggregating responses. Statistical significance of the resulting response is determined based on the analysis of all Tolokers' responses.

How it works:

The model evaluates |L|² parameters for each Toloker, where L is the number of all unique aggregation values.

The parameters used by the model are determined automatically for each pool and are only used only in calculations. You won't see these parameters in the aggregated results.


Because the Dawid-Skene model evaluates |L|² parameters for each Toloker, we don't recommend using it when the Toloker labels < |L|² tasks. Otherwise, the quality of aggregation may be poor.

The result of aggregation is a TSV file with responses. CONFIDENCE: <field name output> indicates the response significance as a percentage.


Data for aggregation can be uploaded any way you want.


The Dawid-Skene model is a non-trivial aggregation algorithm. Check out its features and learn more about the model.

  • The method doesn't guarantee that original Toloker responses will be used for aggregation. The algorithm takes into account Tolokers' quality parameters and response patterns. Consequently, it can produce a result that's different from the Tolokers' responses to this task.

  • The Dawid-Skene aggregation model works with control and training tasks as well as with general tasks. There is a possibility that the OUTPUT:result field for the control task in the TSV file won't match the actual response to this task (GOLDEN:result).

  • If your project has output data marked as "required": false and Tolokers don't fill in this field, it won't be included in aggregation.

    For example, you have 1000 tasks. In 999 of them, Tolokers didn't label the label field, and one Toloker labeled it as label=x. As a result of aggregation, this data field will have CONFIDENCE = 100%, since only one task out of a thousand falls under the aggregation conditions.

How it's calculated

Aggregation only includes accepted tasks.


The main requirement for this aggregation is the output data fields:

Fields that can be aggregated
Fields that can't be aggregated
  • Strings and numbers with allowed values.

    The allowed value must match the value parameter in the corresponding interface element.

  • Boolean.

  • Integers with minimum and maximum values. The maximum difference between them is 32.

If there are too many possible responses in the output field, the dynamic overlap mechanism won't be able to aggregate the data.

The allowed value must match the value parameter in the corresponding interface element.

How do I check it?

If you have doubts that the David-Skene aggregation model works correctly, you can:

  • Reassign tasks and compare the results.
  • Check the task manually.

Aggregation by skill

Analyzes responses based on the level of confidence in the Toloker. The confidence level is determined by the skill you choose. Skills measure the probability of the Toloker completing the task correctly.


  • If your project processes a large amount of data, the aggregation results will be more accurate compared to the Dawid-Skene method.
  • You can choose the output data fields you want to aggregate.


Each user skill has “weight”. The higher the skill, the more we trust the Toloker and believe that their responses are correct.

The result of aggregation is a TSV file with responses. CONFIDENCE: <field name output> indicates the confidence in the aggregated response. In this case, it shows the probability that the response is correct.

How it's calculated

Aggregation only includes accepted tasks.


Pool with dynamic overlap
Pools without dynamic overlap

To run aggregation, you must correctly set up dynamic overlap. To do this:

  1. Select a skill. We recommend to select a skill calculated as the percentage of correct responses in control tasks. This will give you the most accurate aggregation results.

  2. Select the output data fields.

    Output data fields that can be aggregated:

For developers


What is the difference between the confidence in the aggregated response in the Dawid-Skene aggregation model and the confidence in aggregation by skill?
How does the Dawid-Skene aggregation model work?
Why does the Dawid-Skene aggregation model return a result that the Tolokers didn't select?
Where do I see the aggregation progress?
Why might aggregation by Toloker skill be unavailable?
You can't aggregate by skill. When running via the API, I get the error code `ONLY_FOR_POOL_WITH_MIXER`. Why?
Contact support

Last updated: August 3, 2023

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