Methodology Neither of the standard classification systems most frequently used (i.e., the North American Industry Classification System [NAICS] and the Standard Occupational Classification [SOC]) identifies groups of green or environmental industries or occupations. This makes identification of occupations related to specific sectors of the green economy, such as green infrastructure, difficult. The Jobs for the Future (JFF) research team used a multi-step process to identify the SOC codes that belonged to green infrastructure occupations, including reviewing existing research on green infrastructure jobs and collaborating with organizations such as the National Green Infrastructure Certification Program and Ecotrust.18 The team also reviewed occupational profiles on O*Net Online to ensure that duties, job titles, and descriptions corresponded to work identified as green infrastructure work by employers. This report incorporates the JFF team’s list of 30-core occupations as well as additional occupations identified by OAI, INC. in their stormwater training and maintenance needs assessment.19 This report uses OEWS BLS data from 2011 to 202120 and relies on two forms of statistical analysis: percent change and location quotient (LQ). Percent change is calculated by comparing employment numbers in 2021 to 2011by using the following formula:
New Value x 100 Percentage Change = Old Value
A location quotient is a ratio that allows the distribution of employment in one area to be compared to that of a reference area. In other words, it shows the concentration or strength of a particular industry in one location as compared to a larger location. For the purposes of this study, location quotient is used to compare the concentration of industries within the Chicago MSA to the United States. A location quotient that is greater than 1.0 reflects that a particular industry takes up a greater share of local employment than is the case nationwide. For example, the Wind Electric Power Generation industry in the Chicago MSA has a location quotient of .68, which means that compared to the United States as a whole, there is a lower concentration of jobs in this industry in the Chicago MSA. The formula to calculate location quotient is:
LQi =
ei e
( )/( ) Ei E
Section III: Data Analysis
x 100
Where:
ei= Local employment in industryi e = Total local employment Ei= National employment in industryi E= Total national employment
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