On financial markets, it is well known that anticipated changes in policy interest rates have little impact because they have already been priced in. The role of anticipations is very important in the price of any forward-looking goods, a phenomenon that can go beyond financial markets.
Sara Polini applies this idea to labor markets and specifically to the anticipation of movements in the minimum wage. She builds a search and matching model and applies it to Spain where minimum wage changes are usually anticipated, but occasionally not, like after the 2004 terrorist attack that lead to a surprise Socialist government. Anticipated changes lead to a reduction in employment, while unanticipated ones do not. This reconciles the ambiguous and inconclusive results in the literature, which ignored whether changes were anticipated or not.