Driven by data; ridden with liberty.
Continuing on how to judge a party’s local election performance, Shadow Chancellor John McDonnell MP (Labour, Hayes and Harlington) suggested the party’s performance was “making up ground”, and looking for “steady progress” [1, 2].
It was highlighted to the Shadow Chancellor that the main opposition party typically does not lose local council seats, on net, outside of general election years. The last time this happened was in 1985 .
Typically, opposition parties — fresh from electoral defeat — increase their estimated national shares in these local elections. Using the BBC’s projected national share, calculated by Professor John Curtice, we can take the difference of the main opposition party’s performances from the year after the general election, to that general year .
This is the increment in the projected national shares.
In 1984, Labour were the main opposition, and increased their local election PNS by 3% from the general year in 1983. In 1988 and 1993, the jump in this projected national share was 9.5% and 10%, respectively, both under Neil Kinnock.
The Conservatives have bounced back after their three election defeats, with increases of 4% in 1998 and 2002 (from 1997 and 2001, respectively), and 5% in 2006 (from 2005, under David Cameron).
Prior to 2016, the average increment in this estimated national vote share following a general election defeat was 6.4%. The lowest it had been was 3%.
In 2016, Jeremy Corbyn’s Labour increased their projected national vote share from 29% to 31%, or a 2% (percentage point) difference.
Labour had the smallest improvement in their nationally-estimated performance than any main opposition party in the year after a general election, since these figures were calculated in 1982.
Local elections may be no indicator of likelihood of winning a general election, but these performances do not reflect well on Labour.
 Masters, A., 2016. Local Election Performance. In Defence of Liberty. Available from: https://anthonymasters.wordpress.com/2016/05/16/local-election-performance/ [Accessed: 8th May 2016]
 Connor, J., 2016. John McDonnell: these elections are a first step to winning in 2020. John McDonnell. Available from: http://www.john-mcdonnell.net/john_mcdonnell_these_elections_are_a_first_step_to_winning_in_2020 [Accessed: 8th May 2016]
 Kirk, A., 2016. How bad are the 2016 local council elections results for Jeremy Corbyn? Daily Telegraph. Available from: http://www.telegraph.co.uk/news/2016/05/06/local-elections-2016-how-bad-were-the-councils-results-for-corby/ [Accessed: 8th May 2016]
 Curtice, J., 2016. Calculating the Local Election Projected National Share (PNS) in 20115 and 2016. Elections Etc. Available from: https://electionsetc.com/2016/05/04/calculating-the-local-elections-projected-national-share-pns-in-2015-and-2016/ [Accessed: 8th May 2016]