To ask the Scottish Executive, further to the answer to question S3W-31079 by Stewart Stevenson on 4 February 2010, whether the projects mentioned were compared on a like-for-like basis over the same time period; whether there was a common (a) discount and (b) inflation rate, and what account was taken of the complementary investment at Glasgow Airport of a new public transport interchange. All infrastructure projects assessed by Transport Scotland are conducted in line with Scottish Transport Appraisal Guidance (STAG).