Constant sum

The constant sum question is useful for discovering hidden preferences among respondents as it “forces” respondents to allocate points to each item listed.

Respondent view

Respondent view of constant sum question

Constant sum question outputs

Constant sum questions produce the following outputs:

  • Descriptive statistics for number of options for which values were entered including minimum, mean, median, mode, maximum, and standard deviation.
  • A table of correlations between each option
  • The number of participants who saw the question.
Constant sum question outputs

Setting up a constant sum question

Follow these steps to set up a constant sum question:

1. Add question

Navigate to the Add questions tab and click on the Add question button at the bottom of the page.

On the Add or import questions pop-out, select the Add a new question tab and click on the Constant sum question card to add it to the experiment.

Adding the constant sum question

2. Edit question options

Once you add the question, you can adjust the following settings:

  1. Insert the question text in the text box. You can also include formatting and images.
  2. Edit the running total label.
  3. Edit the sum total label.
  4. Specify the sum total available for allocation.
  5. To change the row text, edit the text box next to each row. To add formatting or images, click on the settings for that row. Then check the “Add fancy formatting and pictures to row” checkbox. You can then add formatting or images to the row.
  6. Click on Add row to add additional options.
  7. You can also add an Other option by clicking the Add other. Respondents who select this option will be prompted to type in their answers.
  8. Tick the required question? checkbox if you would like respondents to answer this question before proceeding further.
Constant sum question setup


When should I use a constant sum question?

You should use a constant sum question when:

  • You have a list of features (not more than 5) to prioritise
  • When the features are conceptually easy to understand
  • It is not the main objective of your study

If the main objective of your study is to identify and prioritise features of your product, we would recommend to use Generic Conjoint instead.