How to deal with missing values in variables that are used for matching ？

[mylanhong]

Hello，when we have missing values in variables that are used for matching and these variables largely influence the imbalance, how can we deal with it ? Is there any alternative method ?

[kosukeimai]

You can include the indicator variable for missingness as a covariate.

[mylanhong]

@kosukeimai Thanks for the reply. It is helpful! In addtion, although we can get 'Mean Diff' using the summary() function with matchit object, how can i calculate the SMD (STD Mean Difference) for each variable before and after matching with MatchIt package?

[kosukeimai]

See https://r.iq.harvard.edu/docs/matchit/2.4-20/matchit.pdf