SHOULD LEVEL OF MEASUREMENT CONSIDERATIONS AFFECT THE CHOICE OF STATISTIC

The belief that the level of measurement (nominal, ordinal, interval, ratio) achieved in the data constrains the type of statistic that may be used legitimately for analysis is examined in general, and in an optometric-vision science context. Theoretical considerations indicate that statistical statements about the data may be made independently of the level of measurement, and that although researchers must be concerned about the quality of their measurement, the role of measurement theory is in the interpretation of the meaning of the investigation's results as a whole not in the governance of the choice of statistic. Empirical studies indicate that measurement considerations can be ignored for the purposes of testing the null hypothesis with little or no resultant error. Finally, adherence to the belief that level of measurement considerations limits statistical choice would result in the use of generally less powerful statistical tests-an undesirable and, all things considered, an unwarranted consequence.