We directly compared ensemble spectroscopic measurements to a statistically rigorous single molecule electrical characterization of individual SWNT devices using a high throughput electrical probe station and reported, for the first time, a highly accurate extinction coefficient ratio for metallic to semiconducting SWNTs of 0.352 +/-0.009. The systematic counting of metallic and semiconducting types from solution also allows us to examine the variances associated with device properties and therefore provide the first measure of potential defect generation during processing methods.