For time reasons, I just took a look at the executive summary. But in there one can clearly see the contradiction between different conclusions drawn.
It starts very positive:
"On balance, particularly in recent years, the audit has shown that impact assessment has been effective in supporting decision-making within the EU institutions. In particular, it was found that the Commission had put in place a comprehensive impact assessment system since 2002.So while this sounds good, the summary continues like this:
Impact assessment has become an integral element of the Commission's policy development and has been used by the Commission to design its initiatives better. The Commission's impact assessments are systematically transmitted to the European Parliament and Council to support legislative decision-making and users in both institutions find them helpful when considering the Commission’s proposals."
"Impact assessment reports do not easily reveal their key messages to the reader and comparing the impacts of the various policy options presented in an IA report is often impossible.In other words, the Impact Assessments are a nice innovation but they are largely worthless because they are unclear and not based on good data.
Also, due to a lack of appropriate data, the quantification and monetisation of the impacts of the different options assessed were weak and the analysis often did not provide an adequate basis for a comparison of policy options. In addition, comparing different options was made difficult because of the way in which they were presented in the impact assessment reports."
So Impact Assessments have been introduced but they cannot be an effective tool because their results are blurry as much EU language in decisions and reports is blurry and indefinite. Great!