Year over Year Impact Assessment


I am running an impact assessment for a company that opened their operations in 2017. I want to find out the accumulated economic impact since 2017 until 2023 and will shock the model using Industry Employment. If a company created 50 jobs in 2017, 50 jobs in 2018, 50 jobs in 2019 and maintained the 150 jobs until 2023, what is the best way to find the accumulated economic impact for this company? Would it be:

1. For 2017, use 2017 data year and dollar value to shock model with 50 jobs. 

2. For 2018, use 2018 data year and dollar value to shock model with 100 jobs (sum of 2018 and 2017 jobs) 

3. For 2019, use 2019 data year and dollar value to shock model with 150 jobs (sum of 2019, 2018 and 2017 jobs) 

4. For 2020, use 2020 data year and dollar value to shock model with 150 jobs retained from 2017-19.

5. Repeat #4 for the rest of the years until 2023.

After running these models, I would add the outputs together to find the accumulated impact. However, I know that unlike tax impact, value added, etc. the same job persists from year to year and therefore Jobs are not cumulative? 

Thanks in advance.

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  • Official comment

    Hello Sophia!


    A big consideration to keep in mind here is that while these jobs may be created in 2017, 2018, etc., going into the future they are maintained/supported, not created. When reporting the results of such an analysis, you should use this type of conservative language when describing all of the IMPLAN Results (supported $X Value Added, supported $X of Labor Income, etc.). Additionally, you should report the overall Results in a single Dollar Year (i.e. 2024).


    When thinking about how to report Employment estimates specifically, you are correct to note that a large portion of these workers will be supported over multiple years, and they are only created in the first year. This means that it is important to not sum these Employment estimates across years. If you are to report the total across all years of operations that you model, you should stress the fact that these are not necessarily individual jobs, but actually indicate a single person working for the company for an entire year (and the analysis captures multiple years). Remember, Employment data in IMPLAN follows the same definition as Bureau of Economic Analysis Regional Economic Accounts (BEA REA) and Bureau of Labor Statistics Census of Employment and Wages (BLS CEW) data, which is full-time/part-time annual average. Thus, 1 job lasting 12 months = 2 jobs lasting 6 months each = 3 jobs lasting 4 months each. A job can be either full-time or part-time. Similarly, a job that lasts one quarter of the year would be 1/4 (0.25) jobs. Note that a person can hold more than one job, so the job count is not necessarily the same as the count of employed persons. Another option, that may be easier to communicate and interpret, would be to report an "average annual Employment" value that divides the estimated Employment by the number of years the analysis captures. For example, 100 Employees over a 4 year time frame would be an average annual Employment = 25. You can read more information on Employment in our support article - Employment Data Details.


    Hope this helps! Please let me know if you have any additional questions.



    Michael Nealy

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