A note comparing three measures of subjective probability,their validity and reliability

An attempt was made to compare three measures of subjective probability: estimates out of ten, confidence ratings and time to decide. The validity and reliability of these measures was also investigated. Estimates out of ten and confidence ratings were found to be closely similar measures, but the results from decision times were not so closely comparable. However, the results might be considered to offer sufficient support for the use of decision time when there are strong advantages for a scale which does not require Ss' active participation and deliberation.