Question

In all of the regression models fit by the author, which independent variable appears to be the best predictor of functional status and/or self-perception of recovery? Justify your answer.   

Recovery After Surgery TABLE 3. Regressions of Pain, Fatigue, and Depression on Functional Status and Self-Perception of Recovery 169 137 131 126 3 Months Initial B 3-5 Days B 1 Month B Dependent Independent Variable Variables Functional Status Pain Depression Fatigue .001 .05 .06 .84*** .85** .44** 09 .04 6.94*** .134 .13* 18.82*** 16.69*** R? .308 .291 Self-Perception of Recovery Pain Depression Fatigue -.22* -3.23** -.15 .79 -.25 3.28* .056 -.35*** -3.01*** -.13 21.06*** .31 -08 -1.31* - 22 7.83*** R2 6.24** .123 332 .161 *p<.05. **p<.01. ***p<.001.

Answer 1

Independent variable which is the best indicator of functional status is fatigue

Independent variable which is the best indicator of self perception of recovery is depression

There are multiple ways to determine the best predictor. One of the most easy way is to first see correlation matrix even before you perform the regression. Generally variable with highest correlation is a good predictor. You can also compare coefficients to select the best predictor (Make sure you have normalized the data before you perform regression and you take absolute value of coefficients) You can also look change in R-squared value. Trying removing each one of them and see which variable causes maximum change.