Currently, the Open Probability-based Panel Alliance (OPPA) consists of the following probability-based panels:

OPPA is a mutually non-exclusive and non-binding network of probability-based online or mixed-mode panels committed to facilitating multinational, multiregional and multicultural research. OPPA therefore explicitly invites panel infrastructures to join the alliance. OPPA members share the following joint standards, which must be endorsed by any new alliance member as well:

Survey-based studies running within the OPPA framework are fielded in probability-based (sub-)samples only.

  • Panel member recruitment has been performed following the highest possible standards in each respective country.
  • OPPA members have expressed their support for the principles of openness, transparency, and reproducibility as put forward by the Center for Open Science.
  • OPPA members have implemented, or - considering country-specific restrictions - correspondingly adjusted, the AAPOR Standard Definitions.

New OPPA members are being included throughout the year and decisions are being taken by majority vote among all current members. Expressions of interests to join OPPA can be sent to