They use the terms variety and analysability to define the two dimensions. However the characteristic they ascribe to variety is the amount of information needing to be processed to perform the task, and to analysability the equivocality (or uncertainty) of the information. These two characteristics correspond well to the length and probability dimensions of the Markov chains that represent the information needed to perform the task. The two dimensions used by Draft & Mackintosh can be represented by the two-dimensional complexity-diversity plane of the three-dimensional information space. This model works well for analysis at the task level, but as it has no capacity to cater for the volume of tasks performed it does not generalise well to the organisation. Treating scale as the third orthogonal dimension that emerges at right angles from the page allows this.

Draft and Mackintosh¹ developed from Perrow² a two dimensional model based on the nature of the information processed to perform individual tasks.

Perrow, C. (1967). "A Framework for the Comparative Analysis of Organizations." American Sociological Review 32(2): 194-208

Draft, R. L. and Macintosh, N. B. (1981). "A Tentative Exploration into the Amount and Equivocality of Information Processing in Organizational Work Units." Administrative Science Quarterly 26(2): p207 - 20p