Like many voters, I occasionally receive leaflets from political parties.

This article looks at claims made in a recent Liberal Democrat leaflet.

“WINNING”

In one panel, I can spot multiple problems.

The bar chart is disproportionate and mislabelled

The graphic designer impresses that 82 is roughly one third of 1,334.

Additionally, whilst it is labelled ‘Local election result, May 2019’, the graph is plainly showing the net change in councillors.

Clear winners?

The leaflet asserts:

The Liberal Democrats were the clear winners across the UK in both the local and European elections this year.

As can be seen in the table above, the Liberal Democrats had the third highest count of councillors. However, local elections are local, so making national inferences can be flawed.

We can instead look at the local election national equivalent vote share, calculated by Prof Rallings and Prof Thrasher (University of Plymouth).

Whilst the Liberal Democrats have improved since 2015, the party was the third largest on this measure.

Winning in Europe?

It is also false to claim that the Liberal Democrats were the “winners” in the 2019 European Parliament elections. Across Great Britain, the Liberal Democrats received 20.3% of the total vote.

The Brexit Party received the most votes, with a share of 31.6%.

Surged into first place?

The leaflet cited the following headline in The Times:

The Lib Dems have surged into first place ahead of Labour, Conservatives and the Brexit Party

This headline refers to a single YouGov poll. According to Mark Pack’s poll-base, it was the only published poll since the 2017 General Election to estimate a Liberal Democrat lead.

Note: YouGov experimented with different response formats for their vote intention question. One of these experimental samples (in the two-stage format, on 28–29th May) also had a Liberal Democrat plurality, and another (unprompted, 30th May — 1st June)had a tie with the Brexit Party.

Looking at polling averages (such as by political scientist PhD researcher Jack Bailey) suggests the Liberal Democrats were never ahead on average:

Political parties should take greater care with their graphs, and statements about their public support, in their literature.

This blog looks at the use of statistics in Britain and beyond. It is written by RSS Statistical Ambassador and Chartered Statistician @anthonybmasters.

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