While there is much literature documenting the declining trend of household response rates and resulting effects on nonresponse bias over time, analyses of nonresponse rate and nonresponse bias trends in voluntary establishment surveys are not so widespread. This research project contributes to this rather small strand of literature by analyzing trends in response rates and their relationship with nonresponse bias over the last 8 years of the IAB-Job Vacancy Survey. In addition, we evaluate the performance of various machine-learning approaches to further reduce nonresponse bias relative to the conventional weighting approach.