- The first multi-mode poll was published on 5 March. It had a whopping sample of 9101 respondents. It comprised “web-based surveying combined with face-to-face surveying.
- The second multi-mode poll, published on 12 March, also comprised “face-to-face interviewing and … online surveying”.
- The third multi-modepoll, published on 20 March, saw a different methodology. It was "conducted via face-to-face interviewing, online surveying and via SMS polling".
- The fourth multi-mode poll, published on 22 March, gave rise to a third methodology. It was solely conducted by SMS polling.
Analytically, this flexibility (some would say inconsistency) in methodology makes it difficult to benchmark the house effects that might arise in Morgan's multi-mode polls. In plain-English, with each Morgan multi-mode poll we may well be comparing apples and oranges.
Because these flexibilities affect the underpinning logic for the Bayesian aggregation, I am seriously thinking of removing all Morgan multi-mode polls from the aggregation.