Research was performed in the 1970s and 1980s by all branches of the US military to obtain information on what the goals should be for the electronic technical manuals. Early research was conducted at the Army Communicative Technology Office at Ft. Eustis, the Air Force Human Resources Laboratory (now called Armstrong Laboratory) at Wright Patterson Air Force Base, and the David Taylor Research Center (now called Naval Surface Warfare Center, Carderock Division) in Bethesda, Maryland. Programs developed by the Navy, Navy Technical Information Presentation System (NTIPS) and the Air Force, Computer-based Maintenance Aid System (CMAS), were used along with user surveys, technological analysis and design studies to come up with the basic concepts for IETMs. Based on field tests with technicians maintaining military equipment, the tests found that performance was greatly improved and dramatic improvement occurred for inexperienced technicians. One questionnaire found that 90% of the technicians preferred electronic manuals and found them easier to use.