A C172 Flight Instructor turning base to final at a non-towered airport reported a NMAC with an aircraft on base leg behind them.

Narrative

Aircraft 1 (C172) in a pattern work instructional training flight; maneuvering from left base to final for a full stop landing; was almost hit from the 8 o'clock position during the turn. Aircraft 2 (C172); a commercial pilot renter was engaged in pattern work (15x total) for the day. During their 14th pattern; came within a plane's length of aircraft #1 while on base leg; getting ready to turn final while aircraft number one is currently banking to intercept the final approach. The pattern is typically congested; with about 6 aircraft in the pattern at the time. Potential causes:- lack of situational awareness of both pilots of everyone in the pattern. - improper scanning technique of pilot of aircraft 2. - task saturation of pilot of aircraft 2. Recommendations:- mandate proper scanning technique. Emphasizing looking right (assumed left pattern) on base leg to check the final approach path. Most pilots are assumed overly focusing on looking left towards the runway that they forget that another aircraft maybe on a straight in approach (for whatever reason) or exercising a wider pattern.