It has been a good week for subject-line research. On Monday we started off with what will come as a revelation to many — myself included — that short questions and salutations are not a winning formula, but instead a statistic or fact combined with numbers are.This is in keeping with today’s finding from researchers at Touchstone, reported in eConsultancy, which has found that the age-old mantra of keeping subject lines as simple as possible may not always be a winner. They graded language in billions of emails and then looked at what led to the highest open and click-through rates. At the one extreme there were the type of short, snappy sentences that a young child at junior school could understand. “Cut price tickets” or “Open for voucher codes” were typical at this end of the market. To the other extreme, wording was chosen that could be understood by a university graduate. One example was “Easy, flameless, effective. Cute odor-neutralizing Fragrance Spheres. Just $5.49.”Traditional, empirical advice would suggest that the latter is too long and involved and it would be a quick punchy offer that would get a reader’s attention. Well, actually that did not prove to be the case. Open rates and click-through rates rose steadily as language became more complex. In fact open rates rose from the late teens, in percentage terms, to late 20s and click-throughs from around 10% to 15%.