My dependent variable is firm performance which is made of objective performance (categorical (0-20%, 21-40%,41-60%,61-80%,81-100%), and my subjective performance is ordinal (7 point likert scale). Since they both use different scales I can't merge them into firm performance and I'm not sure if I should convert objective performance to midpoints (for example 0-20% = 0.10) and consider them ordinal or will that hinder the statistical interpretation. Thank you