A first stage circuit for a pipeline ADC first stage combines the functions of an input sample-and-hold-plus-amplifier stage, and the functions of the first analog-to-digital conversion stage of an ADC, including a multiplying DAC, stage-flash ADC comparators, and residue opamp. In one embodiment, the methods and apparatus of the invention provide a technique for classifying data collected about an audience, and creating and grouping qualifiers to those classifications. A dissecting tool assembly is included.