Mormon high school students are encouraged to take seminary, a four-year course of religious study. These one-year courses have annual focus on the following: the Old Testament; New Testament; Book of Mormon; and church history and the Doctrine and Covenants. The objective is to enable each student to be familiar with the scriptures and to assist them in applying gospel principles in their daily life. College age students between the ages of 18 and 30 are also encouraged to take religious classes known as "institute". At private church-sponsored universities and colleges, religion courses are required for graduation. Comparatively little of Mormon doctrinal teaching involves "what traditional Christian catechism would call 'pure theology.'" Mormon "history evolves as part of the church's canon," and an LDS Correlation Committee attempts to ensure that "all church publications, from periodicals to curriculum materials, follow official policy and express official interpretations. This means that sensitive historical issues frequently are downplayed, avoided, or denied."