Hi Soumitra,
We currently do not calculate the R-squared value on the desktop, this change is scheduled for a future release. If you are looking to compare your fits we recommend using the Task Data Comparison tool which lists the AIC, BIC and RMSE among other metrics for fits.
To enable the Data Comparison Tool, click the Data Comparison button on the Fit Task. After a task has run, the Comparison table automatically populates with the metrics of the fit.
Additionally, you can manually calculate the R-squared value for your fit by exporting the fit results and data to the command line, using the Export context menu.
These links provide useful information about how to calculate the R-squared value for a fit.
Please let us know if you have further questions.