A response rate of 27% is within the acceptable range found in published survey research relying on web-based surveys (Cook, Heath, & Thompson, 2000 Cook, C., Heath, F., & Thompson, R. L. (2000). A meta-analysis of response rates in Web-or Internet-based surveys. Educational and Psychological Measurement, 60(6), 821–836. doi:10.1177/00131640021970934[Crossref], [Web of Science ®] , [Google Scholar]; Kaplowitz, Hadlock, & Levine, 2004 Kaplowitz, M. D., Hadlock, T. D., & Levine, R. (2004). A comparison of Web and mail survey response rates. Public Opinion Quarterly, 68(1), 94–101. doi:10.1093/poq/nfh006[Crossref], [Web of Science ®] , [Google Scholar]), but nonetheless, the data were probed for possible response biases. To examine response bias, the available demographics for the respondents were compared. Respondents to the survey were nearly 80% White, as compared to approximately 68% of all employees, demonstrating that White employees were more likely to respond. With respect to department coverage, the response rates were compared by department, and most were found to be within 3–5% of the proportion of actual city employees. The major outlier was the police, who were underrepresented as a function of overall employees, but this was expected, because uniformed officers were excluded from participation.

Boiral and Paillé (2012 Boiral, O., & Paillé, P. (2012). Organizational citizenship behaviour for the environment: Measurement and validation. Journal of Business Ethics, 109(4), 431–445. doi:10.1007/s10551-011-1138-9 [Crossref], [Web of Science ®] , [Google Scholar]) conducted a confirmatory factor analysis (CFA) and validated the following items as measures of eco-helping: (a) I spontaneously give my time to help my colleagues take the environment into everything they do at work; (b) I encourage my colleagues to adopt more environmentally conscious behavior; and (c) I encourage my colleagues to express their ideas and opinions on environmental issues. The following items were validated indicators of eco-civic engagement: (a) I actively participate in environmental events sponsored by my organization; (b) I stay informed of my company’s environmental initiatives; (c) I undertake environmental actions that contribute positively to the image of my organization; and (5) I volunteer for projects, endeavors, or events that address environmental issues in my organization.

Dummy variables were used to operationalize educational attainment, age, and organizational tenure, because when the data were collected, the instrument asked respondents to mark an ordinal group/category for education, age, and tenure. The city did not collect data on a granular/continuous level (e.g., age or tenure) out of concern that individual employees would be identified if they were in a small department. Collecting data in the form of aggregated groups was a decision to help ensure anonymity of participants. In other words, the data were collected in categories, and there was no post hoc aggregation.

Two steps were taken to ensure that the results were, in fact, robust to a violation of the parallel regression assumption. First, multinomial probit models were estimated, and it was found that that the nature of the relationships between the main independent variables and the dependent variable of interest remained consistent across categories. However, the interpretation of the coefficients for each group is relative to an omitted base group. Since the Likert-scale response for each item is 7 points, it creates an unnecessarily complex interpretation of the output. Second, an ordinary least squares (OLS) regression was run, and both the direction and the statistical significance of the relationships remained consistent—demonstrating a degree of linearity across the seven categories.

As noted earlier, other research (e.g., Stritch and Christensen, 2016 Stritch, J. M., & Christensen, R. K. (2016). Going green in public organizations: Linking organizational commitment and public service motives to public employees’ workplace eco-initiatives. American Review of Public Administration, 46(3), 337–355. doi:10.1177/0275074014552470[Crossref], [Web of Science ®] , [Google Scholar]) explores the third aspect of OCB-E, eco-initiative.