Number of Scale Points and Data Characteristics: An Experimental Investigation

Multi-item rating scales are popular in management research where many variables like customer satisfaction, service quality etc. are measured as respondent’s rating in response to statements or questions. Five point and four point scales are quite common and there is no consensus among researchers which of these formats is superior. This study compares the scale characteristics when the same instrument is used with a five point and four point scale. An experimental study was designed where the same items were organized into two different forms one with five point response format and the second with four points format. Respondents were randomly assigned to either one of the formats. When the data is transformed to a common scale, it is seen, that data characteristics like mean, standard deviation, skewness and kurtosis are comparable indicating that there is no change in scale characteristics. However when the correlations are estimated, it is seen that five point scales report a significantly higher correlation. The major implication is that five point scales tend to inflate the reported correlations with a distinct chance of higher type1 error especially when the variables may not be associated.