Building effective data collection and processing systems is not easy, many governments in the world face the challenging task of improving the quality of their data systems. In fact, sufficient good quality data provides the basis for sound performance measurement, monitoring and evaluation activities that help to understand the kinds of initiatives required, ensure that the current initiatives are on track and generate the desired impact. While gaps still persist across policy sectors, the trend is to increase the availability of data to enable sound assessment of the impacts of policies and laws on men and women. Line ministries in charge of specific policy areas most often determine data needs with gender institutions and statistical offices playing an important role in the process.