schools indicate that LGBT students are up to six times more likely than heterosexual students to miss school. Likewise, students in California who endure harassment "because of actual or perceived sexual orientation" are three times as likely as non-harassed heterosexual students to miss school, meaning even heterosexual students harassed for suspected sexual orientation endure some of these problems. Despite such evidence of negative experiences, some LGBT find positive benefits in coming out. Students who are out, while receiving increased harassment from homophobic peers, have lower instances of depression and a greater sense of belonging, a phenomenon well documented in other LGBT studies as well. Though popular belief attributes homosexuality to higher education levels, more current studies suggest otherwise, at least among women. An extensive nationwide survey conducted by the Centers for Disease Control and Prevention indicates that, among women, LGBT identity is inversely related to education level, meaning that for every progressive education level, the percentage of women identifying as LGBT steadily decreases. For instance, while 6.7% of women with no high school diploma identify as lesbian, bisexual, or something else, only 2.9% of women with a bachelor's degree or higher identify that way. The same study showed no statistically significant correlation between LGBT identity and education for men. Studies on LGBT students in college show that LGBT students, while not enduring the same harassment and struggles as LGBT youth in high schools, still have different experiences than their heterosexual peers, sometimes for the better: gay men in college have significantly higher GPAs and are more involved in extra-curricular activities than their heterosexual peers. A study has in fact found a positive correlation between educational attainment and homosexuality and non-exclusive heterosexuality among men. In the study, gay men were significantly less likely to fail to graduate from high school compared to completely heterosexual men (3.94% vs. 9.91%) and were more likely to complete college (43.86% vs. 26.46%). Lesbian and bisexual women, however, report being much less satisfied with their education than heterosexual women in college. Causes There are many possible explanations for the LGBT achievement gap. With extensive studies into the personal experiences of LGBT youth by the GLSEN, the Gay and Lesbian Task Force, and other organizations, some issues relevant to LGBT youth stand out as affecting academic outcomes. The most highly documented and widely studied cause of underachievement by LGBT students is the problem of bullying in schools.