C172 instructor pilot reported an near midair collision in the dpa traffic pattern.

Attributes
ACN	1685887
Time
Date	201909
Local Time Of Day	0601-1200
Place
Locale Reference	DPA.Airport
State Reference	IL
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Direct
Flight Plan	None
Aircraft 2
Make Model Name	Cirrus Aircraft Undifferentiated
Operating Under FAR Part	Part 91
Flight Phase	Climb
Person 1
Function	Instructor Pilot Flying
Qualification	Flight Crew Commercial Flight Crew Multiengine Flight Crew Instrument Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 120 Flight Crew Total 842 Flight Crew Type 800
Events
Anomaly	Conflict NMAC
Miss Distance	Horizontal 100 Vertical 100

Narrative:

Normal training flight. Returning to dpa we were advised to follow traffic on the right downwind runway 20R. While midfield downwind my student called out traffic off our right; I saw a cirrus aircraft climbing rapidly into our flight path. Traffic was within 100 feet. I took control and evasive action to avoid a collision. I reported the incident to tower and another aircraft (not conflict aircraft) reported incident. We continued into the airport and landed with no problems. I called dpa tower to talk about incident after flight.

Original NASA ASRS Text

Title: C172 instructor pilot reported an NMAC in the DPA traffic pattern.

Narrative: Normal training flight. Returning to DPA we were advised to follow traffic on the right downwind Runway 20R. While midfield downwind my student called out traffic off our right; I saw a Cirrus aircraft climbing rapidly into our flight path. Traffic was within 100 feet. I took control and evasive action to avoid a collision. I reported the incident to Tower and another aircraft (not conflict aircraft) reported incident. We continued into the airport and landed with no problems. I called DPA Tower to talk about incident after flight.

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.