shutterstock_326947916_edited.jpg
PScore

The PScore module of Statistics for Data Analysis implements the Propensity Score Matching technique as an alternative to classical multivariate analyses when you need to analyse data from non-randomised studies.

​​

In general, we know that clinical trials are considered the gold standard, i.e. the most accurate diagnostic method for confirming a given doubt.

​​

However, how often have you been unable to organise an experimental study, but have a lot of data available from observational studies?

​​

It is often not possible to organise an experimental study for ethical reasons or because it is costly and time-consuming.

These are the cases where you can use PScore, the Premium Module of the Statistics for Data Analysis solution powered by SPSS.

​​

The PScore, in fact, implements the Propensity Score Matching technique, which is based on data from real cases (health registers, surveys, medical records,...) obtaining results similar to those of randomised trials.

​​

It is therefore very useful to explore the effectiveness of a treatment in a large number of patient subgroups and to achieve greater generalisability (compared to a trial) at a lower cost and time.

​​

Statistics for Data Analysis, allows you to access the Propensity Score matching method easily, quickly and without the need for any specific programming language, with the PScore module, accessible and self-installing thanks to the LaunchBox.

After installation the Propensity Score technique is available in the menu Analyze/ Analyze Add-On/ Propensity Score Matching

After selecting the fields for the different functions and matching preferences, you can click on "Execute":

finestra dialogo Pscore.jpg

On the Source Editor you will find the new fields created by the Propensity Score matching process

PScore_Accoppiamento_edited.jpg

At this point the PScore applied propensity score matching is a statistical technique in which a 'treated' case is matched with one or more 'control' cases based on the closeness/equality of the propensity score values.

This matching helps to recreate a "kind of random allocation" in observational studies, reducing the bias linked to the lack of randomisation.

In the Output environment, you will also find matching diagnostic metrics, including:

A contingency and summary table

TabContingenza-Riepilogo.PNG

The distribution of absolute standard differences

DifferenzaStandardAssoluta.PNG

The distribution of standardised differences with and without matching

Propensity score distributions for treatment category combinations and matching for common support analysis

To summarise, there are only a few steps to apply the Propensity Score Matching technique and thanks to the PScore Module of Statistics for Data Analysis it is very easy to:

  1. Identify the data (large sample size)

  2. Define treatment/control and outcome

  3. Open the PScore from the Menu Analize and select the covariates you are interested in

  4. Estimate the Propensity Score using the dichotomous variable treatment as a dependent

  5. Use the Propensity Score to 'match' groups.

  6. Evaluate the success of 'matching' with the diagnostic methods that automatically appear in the Output.

  7. Perform outcome analysis on the small sample size because it is adjusted by Propensity Score

For further information