You can now apply quotas alongside a filter to segment your participant group. Prolific enables you to set this via the researcher user interface, or by using the FilterSet API.

Intro

Quota sampling offers several benefits for research, market research, or AI testing. It ensures a sample is representative of a target market and reduces the risk of sampling bias. Also, it can lower the cost and time of research, as you don’t need a large or random sample.

Some restrictions to note:

• Quotas only apply to enumerated types.
• This isn’t applicable for intervals. For example, this feature isn’t compatible with specifying ranges, such as an age range.
• The value you give is the weight, so you should give it an integer value.

Creating a FilterSet with quotas

Prolific allows you to apply quotas on enumerated types.

Let's assume you’ve created a group of participants as a filter, which you named ‘handedness’. The values for this filter are represented in order {Left, Right, Ambidextrous} and are available by specifying:

0 for Left

1 for Right

2 for Ambidextrous

{
  "filter_id": "handedness",
  "title": "Handedness",
  "description": "",
  "question": "Are you left or right handed?",
  "type": "select",
  "data_type": "ChoiceID",
  "choices": {
      "0": "Left",
      "1": "Right",
      "2": "Ambidextrous",
    },
}

To specify your quota weights, you’ll need to add this to the body, and you’ll get the quotas applied above.

{
     "filter_id": "handedness",
     "selected_values": ["0", "1", "2"],
     "weightings": {
        "0": 20,
        "1": 35,
        "2": 45,
     },
}

Other uses

You can also fine-tune participant groups via quotas using a FilterSet API patch! To learn more about quotas and demographic sampling, visit our researcher help center.