What explains the drop in turnout in special elections in 2021 vs 2017?
The 2018 midterms and 2020 presidential election in the USA made headlines as having the highest turnout in a century.
Turnout in House of Representatives special elections January to June, 2017 & 2021:
The 2021 turnout rate seems to be less than half given that each district has the same population more or less. This seems on par with the 2013 special turnouts after eyeballing it. I excluded the California district in 2017 because it was basically uncontested.
Why has turnout dropped so much in House specials compared to 2017?