A series of 535 ossiculoplasties were studied to determine statistically significant links between the presence of presenting preoperative clinical features and adverse audiologic results, in order to identify those aspects of case presentation that indicate a good or poor prognosis. Analysis by chi-square testing has identified twelve features classified as surgical, prosthetic, infection, tissue, and eustachian (SPITE) factors. Regrouping the significant features has demonstrated their value in predicting accurately an ossiculoplasty prognosis. The data were used to compare accurately the results of 247 Plastipore procedures and 265 procedures using the Richards Oval-Top hydroxylapatite implant. There was no statistical difference between the series. The use of these factors will permit precise matching of future series to allow accurate comparisons of prostheses, techniques, individual skills, and also surgical philosophies such as the open and closed cholesteatoma management. Most importantly, the SPITE factors permit an accurate preoperative individual assessment when counseling the patient as to the likelihood of success or failure of a proposed ossiculoplasty.