Reduced- form tests of scale effects in markets with search, run when aggregate matching functions are estimated, may miss important scale effects at the micro level, because of the reactions of job searchers. A semi-structural model is developed and estimated on a British sample, testing for...

Reduced-form tests of scale effects in markets with search, based on aggregate matching functions, may miss important scale effects at the micro level, because of the reactions of job searchers. We estimate a semi-structural model on a British sample of unemployed people, testing for scale...