The issue with performance appraisals is that I must judge people based on personal observations as well as 3rd party submissions. Based on this information I must then rate the person. This rating is used for deciding on raises, promotion prospects and, possibly, when retrenchments/redundencies are being decided on. As such there is an element that I cannot be certain is objective (the 3rd party information) and there is a definite financial implication, going so far as to be career influencing and even job influencing. My issue is, would this fall within the guidelines of Lashon Hara, and if so how do I deal with this?

The Chafetz Chaim (Lashon Hara 6, Rechilut 5) explains that even when one is allowed to listen to Lashon Hara (as I wrote to you previously) he is not allowed to believe it and accept it as truth, one can suspect that the information is true and act accordingly, like any important doubtful information. Moreover, the Chafetz Chaim suggests that before listening to the information someone says about others he should ask him to converse only that information which is relevant for future applications. These two rulings apply in your case as well.