Why readability formulas fail
Bertram C. Bruce, Andee Rubin, Kathleen R. Starr · IEEE Transactions on Professional Communication · 1981
Being able to measure the readability of a text with a simple formula is an attractive prospect, and many groups have been using readability formulas in a variety of situations where estimates of text complexity are thought to be necessary. The most obvious and explicit use of readability formulas is by educational publishers designing basal and remedial reading texts; some states, in fact, will consider using a basal series only if it fits certain readability formula criteria. Increasingly, public documents such as insurance policies, tax forms, contracts, and jury instructions must meet criteria stated in terms of readability formulas.