Methods to accurately measure the current-voltage characteristics of organic solar cells under standard reporting conditions are presented. Four types of organic test cells and two types of silicon reference cells (unfiltered and with a KG5 color filter) are selected to calculate spectral-mismatch factors for different test-cell/reference-cell combinations. The test devices include both polymer/fullerene-based bulk-heterojunction solar cells and small-molecule-based heterojunction solar cells. The spectral responsivities of test cells are measured as per American Society for Testing and Materials Standard E1021, and their dependence on light-bias intensity is reported. The current-voltage curves are measured under 100 mW cm(-2) standard AM 1.5 G (AM: air mass) spectrum (International Electrotechnical Commission 69094-1) generated from a source set with a reference cell and corrected for spectral error.