For a research publication, please cite:

• De Cat, C., Gusnanto, A., Kašćelan, D., Prévost, P., Serratrice, L., Tuller, L., & Unsworth, S. (2025). How detailed do measures of bilingual language experience need to be? A cost-benefit analysis using the Q-BEx questionnaire. Bilingualism: Language and Cognition. https://doi.org/10.1017/S1366728925100497

For a non-research publication or a report, please cite the manual:

• De Cat, C., Kašćelan, D., Prévost, P., Serratrice, L., Tuller, L., & Unsworth, S. (2022). Quantifying Bilingual EXperience (Q-BEx): questionnaire manual and documentation. DOI 10.17605/OSF.IO/V7EC8

Q-BEx is free at the point of use.  We want it to continue being free to use by speech and language therapists, teachers, and researchers who do not have access to funding.  If you or your organisation is able to contribute (e.g., from a research grant), please consider donating.

You need to register in order to gain access to the online platform used to run Q-BEx. This will allow you to create projects. Each project will contain a link to the questionnaire which you can send to your respondents. Once you register and log in for the first time, you can access the questionnaire platform by going to https://q-bex.org and clicking ‘Log in’ in the upper right corner of the Homepage.

A member of the Q-BEx team will approve your registration within 2 working days.

Yes, this is one of the key features of the Q-BEx questionnaire. Apart from the two obligatory modules (Background Information, Risk Factors), you can select which other modules you want to include. In several of these modules, it is also possible to make a further selection of which questions to include, depending on the level of detail required.

See also this infographic for an overview.

This depends on how many modules and questions you include, and on how familiar participants are with completing questionnaires of this kind. It can range from 5 or 10 minutes to 45 minutes.

You can access your data in various formats on the relevant project page. The formats are: (i) a .csv file containing all the raw data anonymised, (ii) a .csv file containing a list of respondents’ IDs and names, (iii) a .csv file containing ordered response data and calculations made using the Q-BEx ‘back-end calculator’, and (iv) one .pdf file per child containing a personalised individual report summarising key data. For more information, see the section ‘How to access the data’ in the manual.

Each project expires two years after its publication, and all its data is deleted from the server. Please make sure to download and safely store your data before the expiry date of the project. You will receive an email one month before the expiration date reminding you to do this.

All collected data are stored on a secure server in the UK. For more information, see our Privacy and Cookies Policy.

The Q-BEx team has no access to your participants’ responses.

In order to monitor how the questionnaire is used, the Q-BEx team has access to the meta-data listed below:

• Customisation: what parts of the questionnaire were included?
• Country where the data was collected
• Language of administration and languages selected by the super-user for the questionnaire menus
• Super-user profile: profession/scientific discipline
• General respondent characteristics: caregiver or child
• Whether the study includes an atypical population
• Questionnaire version
• Information gathered by the tool (itemised by respondent) in anonymised form:
  • Completion time
  • Device and browser
  • Child’s age
  • Number of languages used by the family and what these languages are
  • Which questions elicited “I don’t know” responses

Q-BEx complies with the EU General Data Protection Regulation (GDPR). The EU GDPR adequacy decision stipulates that the UK provides adequate protection for personal data transferred from the EU to the UK (and vice versa) under the EU GDPR.

No. You need to create a new project for each language and send the associated link to the parents separately. There is an easy option to clone and modify an existing questionnaire to help you do that.

No. The Q-BEx questionnaire is not a diagnostic tool. However, responses in the Risk Factors module can be used to see if there is any cause for concern regarding a child’s language development. The Individual Reports contain a section to help professionals determine whether a child should be referred for specialist assessment.

We welcome contributions of any kind. Please see the link below for suggestions, or get in touch at qbex@leeds.ac.uk.