Dependent interviewing has been introduced by a number of panel surveys as a means of reducing measurement error, in particular the typically observed concentration of transitions at the seam between waves, the “seam effect.” Little evidence exists, however, of the effects on survey estimates. We report on a large-scale randomised experiment comparing dependent interviewing with traditional independent methods. Proactive dependent interviewing improves the quality of work history data by reducing seam effects in estimates of monthly labour force transitions and eliminates differential seam effects across subgroups. Proactive interviewing does not have any effect on measures of cumulative experience and does not appear to lead to under-reporting of change. Seam transitions in continuous work histories are caused by response errors but can be either visible or hidden, depending on the editing rules used to reconcile reports from repeated panel observations. Proactive methods reduce seam effects by precluding overlapping noncorresponding reports. The potential for eliminating seam effects is, however, limited by item nonresponse to questions about dates.