Python Module for Input-Output Analysis
“Leontief believed that the economy can be broken down into sectors [whose] interrelationship can be described in the form of a mathematical matrix… called an ‘input-output analysis’. Leontief’s initial set of sectors led to a 12×12 matrix…to invert that… it took him [Cornfield] about a week, and the end result was the conclusion that the number of sectors had to be expanded. … [W]ith trepidation, they [Leontief and Cornfield] ended with the simplest matrix they thought would be feasible, a 24×24 matrix. [It is estimated] that it would take him several hundred years of seven-day work-weeks to invert…” [words in brackets added]
David Salsburg (2001), The Lady Tasting Tea, pp.177-8.
That was in the 1940s. Nowadays, inverting a matrix with 100 rows and columns is of no significant problem. On the other hand, input-output analysis has reached a very stimulating level requiring more extensive computation beyond inverting a matrix. The module we prepare here introduces an environment where IO analysis may be conducted in an open and free, yet extensive, computing environment. It is expected that there will be more and more researcher joining this environment, allowing for greater use and access to the IO analysis.
PyIO is a module for Input-Output analysis, written in Python, a general-purpose open source computer programming language. The punch line: Python is freely downloadable and open source means you can actually look at the code, change and distribute it further if you want. One best way to find the latest version is by looking at the official Python website http://www.python.org/.
At this moment, there are several functions available comprising basic input-output analysis. There are as follows:
- Inputting input-output data
- Leontief and Ghoshian inverse
- Impact analysis
- Multiplier analysis: output, income, employment, input
- Updating matrix: regional supply percentage, location quotient
- Updating matrix: RAS method
- Key sector analysis
- Output decomposition analysis
- Multiplier product matrix analysis
- Extraction method analysis
- Push-pull analysis
- IO table aggregation
- Field of influence
The original manual to the PyIO module is written by Suahasil Nazara, Carolyn Dong Guo, Geoffrey Hewings, and Chokri Dridi (2003) and is published as a REAL Discussion Paper 03-T-23. Please make appropriate reference to this manual if you are using the code.