A correlation coefficient is an index number constrained to fall between the range of: 0 and 1. 0 and 100.00 and +1.00 and 0. -100 and 0. Posted on November 16, 2020 | by wp A correlation coefficient is an index number constrained to fall between the range of: 0 and 1.00. 0 and 100. -1.00 and +1.00. -1.00 and 0. -100 and 0.