We’ve long discussed the bias imparted by ex post selection of data depending on whether it went up in the 20th century. Likening such after-the-fact selection to a drug study carried out only on survivors. The Jacoby and d’Arrigo 1989 network was a classic example: the original article reported that they had sampled 36 northern treeline […]
The bias arising from ex post selection of sites for regional tree ring chronologies has been a long standing issue at Climate Audit, especially in connection with Briffa’s chronologies for Yamal and Polar Urals (see tag.) I discussed it most recently in connection with the Central Northwest Territories (CNWT) regional chronology of D’Arrigo et al 2006, in which I showed a remarkable example of ex post selection.
One of the longest standing Climate Audit issues with paleoclimate reconstructions is ex post decisions on inclusion/exclusion of data, of which ex post decisions on inclusion/exclusion of sites/data in “regional [treering] chronologies” is one important family.
