Equivalent of PISA study for standardised assessment of skills on computational thinking and programming?
There is the Educational Testing Service (ETS) Major Field Test for Computer Science, a standardized multiple-choice test. Scores can be compared to those at other institutions, presumably on a per question basis. 

The ETS website includes some sample problems, which include questions about pseudocode, cache variables, trees, graphs, combinatorics, and regular expressions. It looks similar to the CS GRE, which was discontinued in 2013.