Around one-third of Israel Defense Forces infantry officers are religious, with the proportion jumping from only 2.5 percent in 1990 to 31.4 percent in 2007, a new study shows.

The research was published in the military journal Ma'arachot.

Though the steep rise in the number of religious officers has been clearly visible over the past two decades, the army was long reluctant to release concrete data, saying it does not monitor its servicemen's religious beliefs. The issue is also politically sensitive, as the data could exacerbate the left-right and religious-secular debates.

The partial data published in Ma'arachot came from Commander B., an IDF officer on loan to the Israeli police who formerly commanded the elite Shaldag unit. Two years ago, B. wrote a thesis for his degree from the National Security College in which he managed to circumvent the IDF's refusal to release information on religious officers.

Instead of inquiring about officers' current religious beliefs, B. relied on the schools from which they graduated. An officer graduating from a religious high school was listed as religious, and one who graduated from a secular school was listed as secular.

This method obviously has a margin of error, as it does not account for officers who became less religious in the army or religious students who attended secular schools.

According to the extracts from B.'s research published in last week's issue of Ma'arachot, only 26 percent of those who graduated infantry officer courses in 2008 were religious. But throughout the last decade, the proportion of religious officers graduating from such courses has ranged from 22.5 percent to 31.4 percent.

By comparison, only 13.7 of all IDF soldiers graduated from state religious schools.

B. divided the trend into three periods: before 1992, when the proportion of religious officers was minuscule; 1993-2000, when the proportion rose to 15.5 percent; and 2001 to today, when the proportion nearly doubled. Even after the disengagement from the Gaza Strip, he noted, the number of religious officers didn't drop, but rose.

He attributed some of the past decade's surge to the second intifada, which most religious soldiers perceived as "a national battle for their home."

But another factor, he said, is a deeper process underway in the religious Zionist sector's approach to the state and the IDF. He gave particular weight to the emergence of premilitary religious preparatory programs, the first of which opened in 1987. These programs, he wrote, allowed many religious high school graduates to strengthen their faith before taking up full-length military service in combat units.

Before these programs opened, the only option for those who wanted to combine Torah study with army service was a hesder yeshiva. But hesder students usually spend only 16 months in the army, serve in homogenous units made up mostly of fellow hesder students and rarely attend officer courses.

The one-year preparatory programs sent religious soldiers into the army with more confidence in their faith, which reduced their chances of abandoning religion while in service and thus weakened parental and rabbinic opposition to their serving outside the hesder framework. The programs also prepared them physically and mentally for combat service.

According to the article, 80 percent of religious preparatory program graduates join combat units, compared to 40 percent of all soldiers, and 20 to 25 percent become officers, compared to 7 to 9 percent of all soldiers.

B. said his interest in the issue was prompted by seeing the dramatic rise in the number of religious soldiers and officers in Shaldag over the past two decades.