Ridit scores for analysis and interpretation of ordinal pain data

Abstract

Pain studies frequently generate outcome data in the form of ordered categorical responses. Measurement properties of such ordinal variables do not permit straightforward numeric treatment, yet purely categorical (nominal) procedures fail to incorporate the ordered nature of the pain response. This paper describes analysis of ordered categorical data by means of ridit analysis, a simple, yet statistically valid and efficient, technique that yields a highly intuitive interpretation of a treatment effect. The mean ridit comparison of two treatments estimates the probability that a randomly-selected patient from one will have higher pain than a randomly-selected patient from the other. Ridit analysis is illustrated with two examples from a clinical trial involving patients with painful bony metastases subsequent to hormone-refractory prostate cancer.

Evaluation of the results of a randomized controlled trial: how to define changes between baseline and follow-up

“…In general, it is suggested to use nonparametric statistics to analyze changes in ordinal outcome variables. Examples of such nonparametric approaches are ridit analysis [33][34][35] and the so-called "rank-invariant non-parametric method" [36,37]. Another possibility is to use complicated statistical modeling [38,39].…”

Predictive Power Estimation Algorithm (PPEA) - A New Algorithm to Reduce Overfitting for Genomic Biomarker Discovery

“…For each toxicity phenotype, two classes of compounds were identified by querying the DrugMatrix™ database based on severity and incidence of the phenotype they induced. A compound was classified into the positive class if its p-value of observed idit score [35]–[36] for a given phenotype is less than or equal to 0.01 and the percentage of incidence is 100. The ridit analysis is a statistical technique that works with ordered categorical data by evaluating categories in terms of their frequency of occurrence in a control or reference group [35]–[36].…”

“…A compound was classified into the positive class if its p-value of observed idit score [35]–[36] for a given phenotype is less than or equal to 0.01 and the percentage of incidence is 100. The ridit analysis is a statistical technique that works with ordered categorical data by evaluating categories in terms of their frequency of occurrence in a control or reference group [35]–[36]. Conversely, a compound was classified into the negative class if its p-value of observed ridit score for a given phenotype is larger than 0.5 and percentage of incidence is 0.…”

Application of ridit analysis to study the severity of anemia among children, adolescents and pregnant women in Andhra Pradesh

“…This method is used for comparing the ordinal scale responses such as the degree of pain, degree of injury, levels of satisfaction, preference or agreement (Dogan and Dogan, 2007). The ridit method has found applications in different fields of study, including epidemiology, biomedicine, psychology, animal studies, business management and behavioural studies (Wahi et al 1965;Fleiss et al 1979;Venkaiah et al 1992;Donaldson, 1998;Feinstein 2002;Kaushal, 2013;Han et al 2015;Sadhukhan et al 2015 andOriger et al 2015). An excellent review on the ridit analysis and its uses are presented by Brockett & Levine (1977), Selvin (1977), Jansen (1984), Fleiss (1986), Bullimore (1988), Beder& Heim (1990), Sermeus&Delesie (1996), Marion (1996), and IASSL ISSN-2424-6271 51 Bilgin(2003).…”