Following up from our earlier post Critical appraisal of DDAT Controlled Trial Professor Snowling has kindly sent me the full text of their paper.
Snowling & Hulme’s paper criticizes the DDAT study [PDF] on a number of fronts. Firstly because the study did not include a ‘treated control group’ in addition to the ‘treated group’ and the ‘untreated control group’. This third group is required to demonstrate that the children did not improve simply because they were receiving more attention from their parents. Secondly, the way the participants were selected for the two groups meant that the groups were not of equal ability at the start of the study making it difficult to properly assess the relative improvements of the two groups by the end of study. Thirdly the tests used to measure the children’s abilities before and after the 6 month study period had statistical weaknesses which call into question the study’s conclusion. Finally that paper lacked details of the exercise the children did and the raw scores of each of the tests administrated. Without these details other scientists cannot repeat or reanalysis the study, a basic requirement of a scientific study.
It is worth noting that Snowling & Hulme’s paper does not prove that DDAT does not work. It only shows that DDAT haven’t proven their technique works to the rigorous standards required by the scientific community.