Women – and especially poor rural women – suffer not only directly through discrimination or disempowerment, but also in more subtle ways, and for a variety of reasons. A World Bank study in northern Nigeria found that women farmers achieve yields 27% lower than their male counterparts, even when controlling for factors such as input use – even when both use the same amount of fertilizer, women get lower yields. Multiple factors are at work, including lower use of labor (fewer person-days per hectare, more labor being done by older people) and poorer knowledge of best practices. Lower use of labor is because women are less able to hire labor or to ask family members to help; and because they spend a lot of time on household tasks and child care. Lower knowledge levels are generally due to less access to training opportunities and to information.