Note that some studies, particularly older ones, do simply look at women's total education levels.[3] One way to measure education levels is to look at what percentage of each gender graduates from each stage of school. A similar, more exact way is to look at the average number of years of schooling a member of each gender receives. A third approach uses the literacy rates for each gender, as literacy is one of the earliest and primary aims of education.[2] This provides an idea of not just how much education was received but how effective it was.