In its response to Eagle, Chote wrote: “As a number of commentators – including from the Institute for Fiscal Studies and Full Fact – have pointed out, these calculations include a number of judgements and assumptions that others might wish to debate, including the choice of inflation adjustment, whether to include the impact of increased tax and national insurance payments by public sector workers, and whether it is appropriate to quote an average sum across all households when the impact would be felt differentially depending on household income and other factors.
Article source: https://www.huffingtonpost.co.uk/entry/treasury-rapped-strikes-figure-28-billion-households-1000_uk_63a6ba4fe4b0b2e1505a53ae