The percent gain or loss of the invested monies into an investment:
The end value already includes reinvested distributions, so end value + distributed distributions + redemptions gives the value generated by the beginning value + purchases. This field is labeled %Gain-I. The %Gain-I figure is only value weighted. For a performance metric that is both time and value weighted, consider using ROI yields.
Note on Short Positions:
For short positions "purchases" are selling short, or increasing your short position, and "redemptions" are buying shares (covering/decreasing your short position). The absolute value of beginning value + purchases is used in the denominator to provide meaningful figures.