TY - JOUR
T1 - On the need to address fixed-parameter issues before applying random parameters
T2 - A simulation-based study
AU - Ahmad, Numan
AU - Bhowmik, Tanmoy
AU - Gayah, Vikash V.
AU - Eluru, Naveen
N1 - Publisher Copyright:
© 2023 Elsevier Ltd
PY - 2024/3
Y1 - 2024/3
N2 - Count regression models have been applied to model expected crash frequency at individual roadway locations. Random parameters have been increasingly integrated into these models to account for unobserved heterogeneity. However, the introduction of random parameters might also mask issues in the model specification, leading to inaccurate relationships and model interpretation. Two of these specification-related issues are: (1) not considering the appropriate functional form of explanatory variables; and, (2) ignoring the best set of significant explanatory variables. To better examine the need for careful model specification, this study uses synthetic data to demonstrate that the consideration of random parameters does not address the two model specification issues identified. The results from the simulation study illustrate that (a) model specification issues cannot be circumvented by random parameters alone and (b) random parameter models including the exhaustive set of explanatory variables available offer significant model improvements.
AB - Count regression models have been applied to model expected crash frequency at individual roadway locations. Random parameters have been increasingly integrated into these models to account for unobserved heterogeneity. However, the introduction of random parameters might also mask issues in the model specification, leading to inaccurate relationships and model interpretation. Two of these specification-related issues are: (1) not considering the appropriate functional form of explanatory variables; and, (2) ignoring the best set of significant explanatory variables. To better examine the need for careful model specification, this study uses synthetic data to demonstrate that the consideration of random parameters does not address the two model specification issues identified. The results from the simulation study illustrate that (a) model specification issues cannot be circumvented by random parameters alone and (b) random parameter models including the exhaustive set of explanatory variables available offer significant model improvements.
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U2 - 10.1016/j.amar.2023.100314
DO - 10.1016/j.amar.2023.100314
M3 - Article
AN - SCOPUS:85179136978
SN - 2213-6657
VL - 41
JO - Analytic Methods in Accident Research
JF - Analytic Methods in Accident Research
M1 - 100314
ER -