One of the most widely used methods to measure the excess carrier temperature in semiconductors is super band gap time-resolved photoluminescence. We find that under high carrier injection levels the formalism commonly used to extract the electron temperature using this method is erroneous due to the neglect of the role of the quasi-Fermi levels. A method that can be used to obtain accurate carrier temperatures while taking into account the important factors affecting the excess carrier concentration is proposed. The method is used to analyze time-resolved photoluminescence measurements performed on thin GaAs epilayers. It is found that the proposed method accurately corrects the apparent slow electron cooling frequently found in bulk semiconductors.