Incorporating job diversity preference into measuring job accessibility

Diversity is a hot topic in geography and planning. Though a few studies have considered diversity in evaluating accessibility, diversity and the love of diversity have not been simultaneously included in one indicator. This study proposes a method to tackle this challenge, incorporating the constant-elasticity-of-substitution function, with a parameter on the preference for diversity (ρ), into the accessibility indicator of the two-step floating catchment area method (2SFCA). This new method (AC) is implemented to measure Beijing's job accessibility at the jiedao scale which is the basic administrative level in Chinese cities, and compared with the 2SFCA method (AG) and the 2SFCA method with an entropy component for job diversity (AE). All three indicators reveal a similar overall spatial pattern of job accessibility. However, measured by rank of accessibility score, there are some differences between them. Most jiedaos' ranks change when the AE method is used instead of the AG method, though most changes are within a small range. In contrast, when the AC method is used with the ρ-value close to 1, meaning that diversity is almost not valued at all, only a few jiedaos' ranks change. Sensitivity analysis indicates that the accessibility scores' absolute values with the AC method are highly sensitive to the ρ-value, but the overall spatial patterns seem not to be. However, with AC, a small decrease in ρ changes the jiedaos' ranks significantly. Overall, the results indicate that the AC method provides better understanding of accessibility for regions with different preferences on diversity of opportunities.