Flight instructor reported an near midair collision while on short final.

Attributes
ACN	1760212
Time
Date	202009
Local Time Of Day	1201-1800
Place
Locale Reference	AJO.Airport
State Reference	CA
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft Low Wing 2 Eng Retractable Gear
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Flight Plan	VFR
Aircraft 2
Make Model Name	Cessna Aircraft Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Flight Plan	None
Person 1
Function	Instructor Pilot Not Flying
Qualification	Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor Flight Crew Commercial
Experience	Flight Crew Last 90 Days 76 Flight Crew Total 1019 Flight Crew Type 268
Events
Anomaly	Conflict Airborne Conflict Conflict NMAC Deviation - Procedural Published Material / Policy
Miss Distance	Horizontal 100

Narrative:

My student and I performed the practice VOR-a approach into ajo. While in contact with socal approach; we made contact with the CTAF reporting a 6 mile final and 4 mile final call. After the frequency change we heard of traffic in the downwind turning base. The spacing looked appropriate when that traffic turned final and we made another call stating that we were on final behind that traffic. The traffic ahead performed a touch-and-go and we thought we were number 1 for the runway. When we were short final for runway 25; we noticed a cessna less than 100 ft. Off our nose to our 11 o'clock and slightly lower. A go-around was immediately performed to the north and a modified base to final was made to a full stop landing. [At] our final destination a report to ATC was made.I had instructed the student to remove his instrument training device well before the incident occurred.our position was reported several times.it is possible that; given the busy training environment; a radio call was missed; however; the student and I do not recall ever hearing the other aircraft call its position.the slightly lower aircraft was a high wing aircraft. The aircraft we were flying was a low wing aircraft.an effort to visually confirm that final was clear was made by the student and myself.

Original NASA ASRS Text

Title: Flight Instructor reported an NMAC while on short final.

Narrative: My student and I performed the Practice VOR-A approach into AJO. While in contact with SoCal Approach; we made contact with the CTAF reporting a 6 mile final and 4 mile final call. After the frequency change we heard of traffic in the downwind turning base. The spacing looked appropriate when that traffic turned final and we made another call stating that we were on final behind that traffic. The traffic ahead performed a touch-and-go and we thought we were number 1 for the runway. When we were short final for runway 25; we noticed a Cessna less than 100 ft. off our nose to our 11 o'clock and slightly lower. A go-around was immediately performed to the North and a modified base to final was made to a full stop landing. [At] Our final destination a report to ATC was made.I had instructed the student to remove his instrument training device well before the incident occurred.Our position was reported several times.It is possible that; given the busy training environment; a radio call was missed; however; the student and I do not recall ever hearing the other aircraft call its position.The slightly lower aircraft was a high wing aircraft. The aircraft we were flying was a low wing aircraft.An effort to visually confirm that final was clear was made by the student and myself.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.