Construct validity and second-order factorial model

Three second-order factorial models are defined, using the LISREL notation, to assess the univocity of a construct. The first model assumes that the constructs are heterogeneous, the second that they are homogeneous. The third model introduces the notion of partial homogeneity between constructs. Partial homogeneity is defined in terms of a LISREL second-order factor model. In some cases, this model offers a viable alternative to the collapsing of items into a unique scale. An example is given of scales which fit the partial homogeneity model.