This article provides a comprehensive overview of the first-ever national application of the Workload Indicators of Staffing Need (WISN) tool developed by the World Health Organization. The article describes the steps involved in implementing WISN, a human resources management tool, in Namibia, discusses software and data challenges, summarizes key findings relating to health worker shortages and inequities, and reviews the utility of the WISN findings for policy-makers in Namibia. The authors observe that the WISN method can offer credible workload-based evidence to improve the equity and distribution of health workers within a region or across similar types of facilities nationwide. Perhaps most importantly, the WISN tool allows policy-makers to consider the potential impact of decisions on staff requirements before actually making the decisions.