Talk:Propensity score matching

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What does PSM exactly do? I do not understand the method; what about an example? -- Sigbert (talk) 09:05, 17 March 2010 (UTC)

'fraid I don't understand this either: the first para is repetitive and unclear. Three different methods are being commented on (non-randomised, randomised, and PSM): it is not clear which two are being compared and on what grounds.

Aa42john (talk) 07:14, 18 August 2010 (UTC)

Figure doesn't show anything

This article must be written by an undergrad. The figure/table doesn't even have anything to do with propensity score matching; it was obviously plopped in on the page by someone who took it out of context and didn't even attempt any narrative to explain. 24.20.129.195 (talk) 21:47, 10 April 2011 (UTC)

Advantages versus disadvantages

The advantages of PSM should have been clearly stated. The "disadvantages" with the method (overemphasized here) apply to most commonly used methods for estimation using non-experimental data. For many (read most) of the real interesting or policy relevant relevant problems in social sciences, real experimental data is not available or they apply to very specific groups, or specific contexts with very limited relevance in relation to larger parts of the population and policy. So in most cases, if your starting point for research is to study relevant problems with relevant data - you are, whith few exceptions, left with using non-experimental designs.

PSM is a very good alternative in many cases. As with other methods, it does not solve all problems and provide no guarantee of ubiased estimates. To find more unbiased information on PSM and various other methods for evaluation of "treatment effects" , google around a bit and find overviews in doc's or ppt's or and published papers in scientific journals. There is plenty out there. Sample from more than one source - researchers are not unbiased, some are even fundamentalists in methods. Olle W — Preceding unsigned comment added by Olle Westerlund (talk • contribs) 17:38, 1 February 2012 (UTC)

(Moved from above.  Kiefer.Wolfowitz 19:54, 1 February 2012 (UTC))

Unsourced

 Kiefer.Wolfowitz 19:57, 1 February 2012 (UTC) I removed these two paragraphs, which lack citations and whose authors are less relevant than Rubin, Rosenbaum, and Pearl.

Removed stuff

Howard Bloom, MDRC, sees PSM as a somewhat improved version of simple matching, but with many of the same limitations

• Inclusion of propensity scores can help reduce large biases, but significant biases may remain
• Local comparison groups are best—PSM is no miracle maker (it cannot match unmeasured contextual variables)
• Short-term biases (2 years) are substantially less than medium term (3 to 5 year) biases—the value of comparison groups may deteriorate

Michael Sosin, University of Chicago also identifies following problems with PSM:

• Strong assumption that untreated cases were not treated at random
• Argues for using multiple methods and not relying on PSM

Stratification matching vs stratified sampling

Under the matching method, “stratified matching” is pointed to the page of “stratified sampling”. Are they the same technique? 209.212.21.198 (talk) 22:55, 24 October 2022 (UTC)