A Campbell systematic review sums up the best available research about the impact of a specific intervention by synthesizing the results of several studies.
The impact of a social intervention is the difference between how people do if they receive the intervention and how they would have been doing if they had not received the intervention. Methodologically, it is not easy to isolate this impact from other factors affecting the participants at the same time. A classic method is randomised controlled trials, where eligible participants are randomly assigned to a treatment group and a control group (where the control group can be on a waiting list for the intervention or get a different intervention). This design prevents systematic differences between the people receiving the intervention, and the people with whom they are being compared. However, also other research designs can be used to carry out impact assessments. Common for these is the comparison between people receiving the given intervention, and people not receiving the intervention; i.e. a control group.
This is how it works
The Campbell Method consists of four basic steps: Listing criteria for the scientific approach to the studies included in the analysis, searching systematically for studies using a standardised search strategy, assessing all studies found according to the inclusion criteria and finally analysing the studies which meet the inclusion criteria.
In addition, a fundamental part of the process is that all methodologies, criteria and choices in the systematic review are documented and made public in order to ensure transparency. In practice, a protocol (i.e. work plan) for the systematic review process is produced as well as the actual systematic review. All material is approved by the independent research group, the Campbell Collaboration, as both the protocol and the systematic review are peer-reviewed by specialists and methodology experts. Finally, both the protocol and the Campbell review is published in the Campbell Library.
How can the results be used?
A Campbell systematic review synthesizes research about the effect of a specific intervention measured on specific outcomes for a specific population in an international perspective. Knowledge about effectiveness is increasingly important as resources for social interventions become scarcer in many countries, along with other types of knowledge. Furthermore, knowledge about effectiveness can also be included in cost-benefit analyses.
The Campbell systematic review is thus a contribution to the overall understanding of a given intervention and helps decision-makers make informed decisions about which interventions to use; decisions that are not made on the basis of results about effects alone, but in interaction with other types of knowledge.
- SFI Campbell is a division within SFI - Danish National Centre for Social Research
- We produce and disseminate systematic reviews of the effects of social interventions according to the Campbell Method
- Ongoing systematic reviews include active labour market policies, treatment of substance abusers and deployed soldiers.
For more information, visit www.sfi-campbell.dk
At SFI Campbell, we believe that knowledge is a non-exact, multifaceted concept, where our systematic reviews have a clear role in answering the highly relevant questions: does the intervention work as intended, to what extent does it work and for whom? The advantage of a Campbell systematic review is that the method is systematic, documented and transparent, so it is clear how the result has emerged. And to answer these questions, we have to use highly rigorous scientific methods. By doing this, our results provide pieces for the overall knowledge jigsaw puzzle.