There are two sorts of councils and hence council elections in the UK. Those called “principal authorities”, which cover bodies such as* county councils, district councils, unitary councils and London Boroughs. Then there is a lower tier made up of parish, community and town councils.
Politically, there is a key difference between the two which explains why systematic analysis of council by-elections, vote share changes in them and collections of local by-election results all cover (only) principal authorities. That’s true for academics, the better sort of political pundits, reference works and the like.
Parish, community and town council elections are frequently uncontested, which immediately raises an issue about calculating vote shares and swings. Moreover, it’s usual for a candidate who is a member of a political party to stand as an ‘independent’, with the voters quite possibly never knowing which party they belong to. This is exacerbated by the different legal framework for these elections, but even when candidates put out leaflets, party names feature very rarely compared with principal authority contests. This means that even if there was, say, a Labour candidate last time and one again this time, looking at the change in their vote often doesn’t really reveal anything about Labour. Finally, there is a pragmatic reason for excluding the parish, town and community elections – their results are very, very hard to track down and there is no comprehensive dataset of all such results.
Hence, my own posts almost exclusively concentrate on principal authorities with only rare exceptions such as when there’s the pleasure to share of someone I know being elected (congratulations Antony).
I try to stick to this quite rigorously because there’s a danger of self-deception in slipping into commenting on, publishing about or even just simply reacting to other parish, town or community council results that come your way via a social media feed or timeline. It’s that you end up with a very distorted view of what’s going on – your friends share with you the exciting outliers (‘hooray! we won the first seat for 163 years in this village!’) and you don’t hear about the mundane reality that makes up the bulk of results (‘two independents were elected unopposed, yet again, and three people had to be co-opted to fill up the other vacancies’).
It isn’t a random representative selection of such results you end up ingesting. It’s a biased selection. Looking at only a biased selection of facts is never a good move, however well-meaning the intent and however copper-bottomed the individual facts. It’s still a biased selection, just as only reporting opinion polls which show your own party going up would be.
Which is why whenever you cheer you own side winning a town, parish or community council seat you shouldn’t follow it up with any view on how your own side’s fortunes are going unless there is some special extenuating circumstance.
* I write “such as” because there is also the City of London, the Isles of Scilly and the Greater London Authority.