Database Validation

Validating the database is an important final step in the data development process.

Validation Process

Once the national model is complete and balanced, it is checked thoroughly for errors. Models are built and multipliers generated. All values are distributed to the states and counties based on the procedures outlined here. Once the data have been distributed to the states and counties, an extensive validation process takes place. State and county models are built and evaluated. The data are also passed through a program that calculates ratios on every value in the database. Any outliers are examined and either documented or fixed if a program or data bug is the cause. Once this process is complete, the databases are released to the public. Users should always examine their study area and make changes if required. 

Force Account Adjustment

To conform to I-O accounting definitions, IMPLAN industry data are subjected to an adjustment. This adjustment is called the force account adjustment and is an attempt to keep production activities consistent across sectors. For example, some non-construction industries, such as mining, have a large construction component. The force account construction adjustment moves the construction activity from the mining sector to the appropriate construction sector. The net result is that mining values may be slightly smaller than published estimates and the construction values may be slightly higher. Construction sectors can have production functions very different than the Industry using the constructed elements. Another highly affected sector is Hotels and Lodging. Restaurant, retail, and gaming activities that take place in hotels are moved to their respective sectors, thereby reducing the Hotels and Lodging sector to ~70% of its original size.

By keeping the activities separate, expenditures made during production will be more accurately allocated.