When working with more than one region in an Multi-Regional Input-Output Analysis series that has Direct Effects, the sequence for Model development can be somewhat confusing to conceive as multiple iterations of the Models need to be created to avoid cross-linkages in the MRIO Scenarios.
When building Multi-Regional Input-Output Analysis Scenarios, it is important to remember that you:
- Cannot have any overlapping geographies between Model regions
- Only one Model in any set of linkages can include Direct Effects. Therefore, a new series of Models needs to be built for every additional region that has Direct Effects.
To examine this, let's look at an example analysis where three (3) regions in a state all have simultaneous Direct impacts for which we want to see the ripple effects to:
- the other two counties
- the rest of the state (ROS) - assembled by aggregating county files for the ROS from a state package.
Our regions and values for this example are:
- Larimer County $2MM in Hotel Services
- Weld County $900,000 of Hotel Services
- Arapahoe County $3.5MM of Hotel Services
Note that regions do not have to be contiguous to do MRIO analysis. Thus while Weld and Larimer counties are contiguous, Arapahoe County is not adjacent to either of these counties.
For the impact on Larimer County, we will need four (4) Models.
|ROS (less Larimer, Weld, and Arapahoe Counties)1|
For the impact on Weld County, we need a second set of four Models.
|ROS (less Larimer, Weld, and Arapahoe Counties)2|
For the final impact, on Arapahoe County, we need a third set of four Models.
|ROS (less Larimer, Weld, and Arapahoe Counties)3|
To help keep the Models clearly delimited from one another, we recommend using a naming convention that will allow you to know which Model in the group is the primary Model where Direct Effects are taking place.
We also recommend creating each set of Models in a separate folder in your Models folder so that you do not accidentally cross-link Models.
Once these 12 Models are built, they can be linked to the remaining Models in their group through the MRIO Scenario screen.
Summing MRIO Results
To create a total set of results, you will need to sum together the four (4) results sets from the (3) Model sets.
We recommend doing this by selecting each of the results sets in each Directly Effected Model and exporting these to Excel
- Results of all three regional runs can be summed without concerns of double-counting.
- Results can be summed into one total result set for the state or summed results for each region
- Direct Effects will only occur in the target region where the initial impact occurred.
Finding the Multiplier
Multi-Regional Input-Output Analysis doesn't have a preset Multiplier table you can employ to determine the MRIO Multipliers. However, it is very easy to calculate an MRIO Multiplier from your study.
- For individual study MRIO Multipliers, sum all the impacts associated to that Scenario and divide the Total Impact over the Direct Impacts.
- For a total study MRIO Multiplier, sum all the impacts in the state and divide by the sum of the three Direct impacts.