[R-meta] Converting smd to r-coefficients

[Tarun Khanna]

Dear all,

In the meta regression that I am conducting, there were two types of primary studies. One that employed regression analysis and others that employed a difference of means test. I calculated an r coefficient for the first set of studies and standardised mean differences for the second set and then converted these into r coefficients. I conducted the final analysis on r coefficients. In the meta regression models I added “statistical technique” as a moderator variable and the coefficient of the variable signifying mean differences studies is significantly negative.

I'm not sure if this difference being captured in the regression is on account of difference in the underlying studies or whether conversion of smd to r coefficients might have somehow biased estimates from the second set of studies downwards. Is this this possible? What can I do to check?

Best regards
Tarun


Tarun Khanna
Research Associate

Hertie School

Friedrichstraße 180
10117 Berlin ∙ Germany
khanna using hertie-school.org ∙ www.hertie-school.org<http://www.hertie-school.org/>

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