Wegman report

The Wegman Report (officially called the Ad Hoc Committee Report on the 'Hockey Stick' Global Climate Reconstruction) was prepared in 2006 by three statisticians led by Edward Wegman at the request of Rep. Joe Barton of the United States House Committee on Energy and Commerce to validate criticisms made by Stephen McIntyre and Ross McKitrick of reconstructions of the temperature record of the past 1000 years, in particular the reconstructions by Mann, Bradley and Hughes which had become the focus of the hockey stick controversy.

Investigations of paleoclimate date back to the 1930s. but quantitative methods were slow to come into use. In the 1960s, Hubert Lamb generalised from historical documents and temperature records of central England to propose a Medieval Warm Period from around 900 to 1300, followed by Little Ice Age. This was the basis of a "schematic diagram" featured in the IPCC First Assessment Report beside cautions that the medieval warming might not have been global. The use of proxy indicators to get quantitative estimates of the temperature record of past centuries was developed, and Bradley & Jones 1993 introduced the "Composite Plus Scaling" (CPS) method used by most later large scale reconstructions. Their study was featured in the IPCC Second Assessment Report, and in the United States House Committee on Science its findings were disputed by Pat Michaels.