A polling survey has a number of limitations. The sample size (see Annex A for details) limits meaningful subgroup analysis and the survey is based on non-probability research panels, which means representativeness is achieved using quotas. Furthermore, the nature of online research inherently excludes those who do not have internet access. The data source nevertheless provides useful and timely information, as long as appropriate caveats are applied.
As the survey has been conducted using a quota sample, rather than a random probability sample, statistical significance can only be used on an indicative basis. Differences over the survey waves are only highlighted if they are likely to be significant, however not all significant differences have been described.