Transitions to New Technologies - Software
IIASA Logistic Substitution Model II

About

The "IIASA Logistic Substitution Model II" is a software tool to estimate the parameters of technological growth and substitution processes. The program allows to:

• Analyze time series data that follow a (single) sigmoid trajectory by estimating the parameters of a variety of growth curves from empirical data.
• Analyze the market shares of several competing technologies by applying a logistic substitution (Marchetti/Nakicenovic) model to multiple time series.
• Analyze absolute production/sales amounts per technology and for the total market volume of all technologies taken together in combining above two model features.

Specifics

Although LSM2 includes some of the most popular functions used in the diffusion literature it is not exhaustive and only allows for analysis of single, and positive growth processes and of logistic substitution processes based on relative market shares. Users interested in a wider portfolio of growth curve functions are referred e.g. to the MINUIT package at CERN or the Loglet software package for analysis of overlapping S-curves at Rockefeller University.

Model estimations are user defined in terms of model selection, data periods used for parameter estimation, or in terms of exogenously specified scenario values (used e.g. to analyze the dynamics of the system under introduction of an entirely novel technology).

Thus, while LSM2 is a fairly flexible tool it does not dispense the user from exercising his/her own judgment as to the appropriateness of a particular model or of a particular model fit to empirical data. Finally, it should be noted that LSM2 is a tool for descriptive analysis, which typically is only the first step of a more comprehensive analysis of technological evolution, including also causal factors. An extension of the model in the latter direction is planned.

History and Current Implementation

The original model was first formulated in 1979 by C. Marchetti and N. Nakicenovic at IIASA. The model was originally implemented as a mainframe Fortran program with limited portability. In 1994 the original model code was reprogrammed by M. Posch into two separate software packages FIT (for estimation of S-curves) and LSM (for estimating logistic substitution patterns) and ran on the DOS/Windows platform of that time.

The 2005/2006 version of LSM2 was developed by P. Kolp at IIASA. It merged the two separate software packages from 1994 into an integrated platform, added an improved user interface, and enhanced its portability. The program can now either be downloaded onto a local computer or alternatively run directly via the web at IIASA.

Through implementing the application in Java/Swing an up to date user interface (utilizing the Swing widget set) was added and LSM2 also made available - without even recompiling it - for all OS platforms where a Java Standard Edition runtime environment is available, including Windows (98, NT, W2K, XP), Mac OS, and Linux/UNIX.

The current version of LSM2 while having been tested extensively is provided on an "as is basis" (see LSM2 license).

Feedback and suggestions are most welcome. Please address them to: tnt@iiasa.ac.at

Further technical details can be found on the LSM2 features page.

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Last updated:09 Nov 2006