Walwei, Ulrich - In: Mitteilungen aus der Arbeitsmarkt- und Berufsforschung 28 (1995) 4, pp. 516-526
"It cannot be taken for granted that fulling a job vacancy via the employment services (or via other job-seeking measures) will lead to additional employment or even to less unemployment. Behind the attempt to measure the gross effect (e.g. in the form of the number of placements matched) always...