The identification of pre-operative factors that accurately predict the EOR and outcomes among patients undergoing transsphenoidal pituitary adenoma resection enables physicians to make effective management decisions. The prospective multi-center TRANSSPHER study evaluated 221 patients across 7 institutions. The study compared 15 surgeons’ preoperative surgical goals with corresponding EORs as determined by postoperative MRI. Pre- and postoperative endocrine status was also examined. The study showed that surgical goal was a poor predictor of the extent of resection and associated endocrine outcomes at 6 months. Strong predictors of GTR were Knosp grade 0-2 (p=0.004) and small tumor size (p=0.001). Surgical goal was a poor predictor of degree of resection (p=0.14). This manuscript provides data on a large series of pituitary patients with rigorous data analysis. This data provides guidance for physicians in utilizing Knosp grade to evaluate the predicted degree of resection and potential need for adjuvant therapy.