A program designed to improve the accessibility of an existing program or computer system. IFEs are useful where complex and highly sophisticated software already exists. The expertise to use this software may take considerable time to acquire; the purpose of an IFE is to alleviate this. The IFE may contain knowledge about the domain of the software (e.g. mathematics or finite element modelling) and also expert knowledge about how best to use the software to solve problems in that domain. IFEs have been built for a wide range of programs (e.g. statistics, finite element modelling, and ecology) and are potentially important in widening the availability of existing software.