Difference between revisions of "Quasi-Experimental or Non-Experimental Designs"
***** (***** | *****) m |
***** (***** | *****) m |
||
| Line 2: | Line 2: | ||
= <span style="line-height: 20.390625px;">Matching Methods or Constructed Controls</span> = | = <span style="line-height: 20.390625px;">Matching Methods or Constructed Controls</span> = | ||
| − | ''Matching methods or constructed controls'', in which one tries to pick an ideal comparison that matches the treatment group from a larger survey. The most widely used type of matching is ''propensity score matching'', in which the comparison group is matched to the treatment group on the basis of a set of observed characteristics or by using the “propensity score” (predicted probability of participation given observed characteristics); the closer the propensity score, the better the match. Agood comparison group comes from the same economic environment and was administered the same questionnaire by similarly trained interviewers as the treatment group.<ref name=" | + | ''Matching methods or constructed controls'', in which one tries to pick an ideal comparison that matches the treatment group from a larger survey. The most widely used type of matching is ''propensity score matching'', in which the comparison group is matched to the treatment group on the basis of a set of observed characteristics or by using the “propensity score” (predicted probability of participation given observed characteristics); the closer the propensity score, the better the match. Agood comparison group comes from the same economic environment and was administered the same questionnaire by similarly trained interviewers as the treatment group.<ref name="Worldbank - http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2000/08/19/000094946_00080705302127/Rendered/INDEX/multi_page.txtfckLR">Worldbank - http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2000/08/19/000094946_00080705302127/Rendered/INDEX/multi_page.txtfckLR</ref><br/> |
<br/> | <br/> | ||
| Line 8: | Line 8: | ||
= Instrumental Varialbles or Statistical Control Methods = | = Instrumental Varialbles or Statistical Control Methods = | ||
| − | ''Instrumental variables or statistical control ''methods, in which one uses one or more variables that matter to participation but not to outcomes given participation. This identifies the exogenous variation in outcomes attributable to the program, recognizing that its placement is not random but purposive. The “instrumental variables” are first used to predict program participation; then one sees how the outcome indicator varies with the predicted values.<ref name="worldbank"> | + | ''Instrumental variables or statistical control ''methods, in which one uses one or more variables that matter to participation but not to outcomes given participation. This identifies the exogenous variation in outcomes attributable to the program, recognizing that its placement is not random but purposive. The “instrumental variables” are first used to predict program participation; then one sees how the outcome indicator varies with the predicted values.<ref name="Worldbank - http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2000/08/19/000094946_00080705302127/Rendered/INDEX/multi_page.txtfckLR">Worldbank - http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2000/08/19/000094946_00080705302127/Rendered/INDEX/multi_page.txtfckLR</ref><br/> |
<br/> | <br/> | ||
| Line 14: | Line 14: | ||
= Reflexive Comparisons = | = Reflexive Comparisons = | ||
| − | ''Reflexive comparisons'', in which a baseline survey of participants is done before the intervention and a follow-up survey is done after. The baseline provides the comparison group, and impact is measured by the change in outcome indicators before and after the intervention.<ref name="worldbank"> | + | ''Reflexive comparisons'', in which a baseline survey of participants is done before the intervention and a follow-up survey is done after. The baseline provides the comparison group, and impact is measured by the change in outcome indicators before and after the intervention.<ref name="Worldbank - http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2000/08/19/000094946_00080705302127/Rendered/INDEX/multi_page.txtfckLR">Worldbank - http://www-wds.worldbank.org/servlet/WDSContentServer/WDSP/IB/2000/08/19/000094946_00080705302127/Rendered/INDEX/multi_page.txtfckLR</ref><br/> |
<br/> | <br/> | ||
Revision as of 21:02, 4 April 2013
Matching Methods or Constructed Controls
Matching methods or constructed controls, in which one tries to pick an ideal comparison that matches the treatment group from a larger survey. The most widely used type of matching is propensity score matching, in which the comparison group is matched to the treatment group on the basis of a set of observed characteristics or by using the “propensity score” (predicted probability of participation given observed characteristics); the closer the propensity score, the better the match. Agood comparison group comes from the same economic environment and was administered the same questionnaire by similarly trained interviewers as the treatment group.[1]
Instrumental Varialbles or Statistical Control Methods
Instrumental variables or statistical control methods, in which one uses one or more variables that matter to participation but not to outcomes given participation. This identifies the exogenous variation in outcomes attributable to the program, recognizing that its placement is not random but purposive. The “instrumental variables” are first used to predict program participation; then one sees how the outcome indicator varies with the predicted values.[1]
Reflexive Comparisons
Reflexive comparisons, in which a baseline survey of participants is done before the intervention and a follow-up survey is done after. The baseline provides the comparison group, and impact is measured by the change in outcome indicators before and after the intervention.[1]
Further Information
