What is Structural Equation Modeling?

Structural Equation Modeling (SEM) is an extremely broad and flexible framework for data analysis, perhaps better thought of as a family of related methods rather than as a single technique. Its origins can be traced back to Psychologist Charles Spearman at the turn of the 20th century and Geneticist Sewall Wright in the immediate aftermath of WWI. Many others have had a hand in its development, notably Karl Jöreskog and Peter Bentler. Covariance Structure Analysis and LISREL, the name of a program Jöreskog co-developed, are other terms occasionally used interchangeably with Structural Equation Modeling. What is its relevance to Marketing Research?