An Item Response Theory to Analyze the Psychological Impacts of Rail-Transport Delay

Abstract

Questionnaire instruments have been used extensively by researchers in the literature review for evaluation of various aspects of public transportation. Important implications have been derived from those instruments to improve various aspects of the transport. However, it is important that instruments, which are designed to measure various stimuli, meet criteria of reliability to reflect a real impact of the stressors. Particularly, given the diverse range of commuter characteristics considered in this study, it is necessary to ensure that instruments are reliable and accurate. This can be achieved by finding the relationship between the item’s properties and the underlying unobserved trait, being measured. The item response theory (IRT) refers to measurement of an instrument’s reliability by examining the relationship between the unobserved trait and various observed items. In this study, to determine if our instrument suffers from any potentially associated problems, the IRT analysis was conducted. The analysis was employed based on the graded response model (GRM) due to the ordinal nature of the data. Various aspects of the instruments, such as discriminability and informativity of the items were tested. For instance, it was found while the classical test theory (CTT) confirm the reliability of the instrument, IRT highlight some concerns regarding the instrument. Also, the person fit assessment measure, for instance, highlights some concern regarding respondents answering some of the questions due to lack of interest, choosing answers randomly. Not many studies have examined instruments’ reliability in determining the psychological impacts of public transportation on commuters in the way that was performed here.

Application of Item Response Theory (IRT)-Graded Response Model (GRM) to Entrepreneurial Ecosystem Scale

“…The outcome measure is based on theta in IRT. In contrast, in CTT, the outcome measure is based on the sum of the score distribution [24].…”

“…Source: (Rezapour et al (2021) [24]). The probability of selecting the ith item is provided in Equation ( 2), θ m = (α i , β i ) is the ability or latent trait for individual m, α i is the discrimination parameter for item i, location of extremity boundary for item i defined as difficulty parameter is β i (if constrained can be considered constant for all items), and θ m is the ability of respondents m on various questions or items.…”

“…Using the IRT-GRM, the value of α > 1.0, is considered highly discriminant. Difficulty values are within the range of −3 to 3 [24]. The item under the element market, that is, mar5, has the lowest discriminative value.…”

Properties of a Transport Instrument for Measuring Psychological Impacts of Delay on Commuters, Mokken Scale Analysis

“…Despite the importance of instrument evaluation, the majority of past studies only employed the traditional Cronbach alpha method, and a single study employed the IRT in the field of transportation ( Rezapour et al, 2021 ). So a comprehensive application of MSA is missing from the past studies in the context of transport.…”

“…Despite the importance of evaluating instruments, the authors have only found a single study conducted with the help of IRT ( Rezapour et al, 2021 ) in the context of transportation, while no study has employed the MSA technique in the context of transport psychology. Implementation of the MSA is important due to the possible limitations of the IRT.…”