Big Bloom Theory !

Bloom's taxonomy is a set of three hierarchical models used to classify educational learning objectives into levels of complexity and specificity. The three lists cover the learning objectives in cognitive, affective and sensory domains. The cognitive domain list has been the primary focus of most traditional education and is frequently used to structure curriculum learning objectives, assessments and activities. As with most theoretical models, they are controversial even while commonly used. (citation needed)

Here is an image illustrating the hierarchy.