Skip to main content

Single Difference (in impact evaluation)

Go Search
Home
About
New Atlas
Atlas, A-Z
Atlas Maps
MPP/MPA Programs
Subjects
Core Topics
Illustrative Courses
Topic Encyclopedia
Concept Dictionary
Competencies
Career Tips
IGOs
Best Practices Project


 
PPGPortal > Home > Concept Dictionary > S > Single Difference (in impact evaluation)
 
Single Difference (in impact evaluation)

The difference in the output or outcome either (i) before versus after an intervention, or (ii) between project and comparison groups.

(OECD, 2007, p. 7)

---------------------------------

The difference in the output or outcome either (i) before versus after the intervention, or (ii) between project and comparison groups. Before-versus-after is not a good impact measure as it fails to control for other factors. The single difference project versus comparison groups fails to allow for differences between the two groups which may have existed prior to the intervention. The double difference takes care of these two problems.


References

Organisation for Economic Co-operation and Development (OECD) (2007). “Outline of Principles of Impact Evaluation”. Retrieved on June 25, 2008, from
http://www.oecd.org/dataoecd/46/16/37671602.pdf.
     
Single Difference (in impact evaluation)

The difference in the output or outcome either (i) before versus after an intervention, or (ii) between project and comparison groups.

(OECD, 2007, p. 7)

---------------------------------

The difference in the output or outcome either (i) before versus after the intervention, or (ii) between project and comparison groups. Before-versus-after is not a good impact measure as it fails to control for other factors. The single difference project versus comparison groups fails to allow for differences between the two groups which may have existed prior to the intervention. The double difference takes care of these two problems.


References

Organisation for Economic Co-operation and Development (OECD) (2007). “Outline of Principles of Impact Evaluation”. Retrieved on June 25, 2008, from
http://www.oecd.org/dataoecd/46/16/37671602.pdf.

Approved for glossaryposting by Ben Eisen on December 7, 2010


Important Notices
© University of Toronto 2008
School of Public Policy and Governance