Comparison(redirected from comparison groups)
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comparing a gauge or quantity to be measured with a quantity that is reproducible in the measuring process.
Comparisons are made by instruments such as the equal-arm balance, the electric potentiometer, the photometer bench with a photometer, and the comparator for linear standards.
an act of thought by means of which the content of being and cognition is classified, ordered, and evaluated; in comparison, the world is understood to be “coherent” diversity. The act of comparison consists of the pairing of objects for the purpose of clarifying their relationship. Essential to this are the conditions, or bases, of comparison—the attributes that determine precisely what the possible relationships are between objects.
Comparison has meaning only in an aggregate of “homogeneous” objects that form a class. The comparability of objects in a class (tertium comparationis) is realized in terms of the attributes essential for a particular examination; objects comparable in terms of one basis may be incomparable in terms of another. For example, all people are comparable in terms of age, but not all are comparable with respect to “being older.”
The simplest and most important type of relationships revealed by means of comparison are the relationships of identity (equality) and difference. Comparison of this type leads in turn to the concept of universal comparability, that is, the notion that it is always possible to answer the question of whether objects are identical or different. Objects of visual experience are always comparable, although the condition of visibility, or observability, is a significant restriction. In theory, the visual comparison of objects is often impossible, and to compare objects it is necessary to resort to inferences and, eventually, to certain abstractions from which the inferences have been deduced. The supposition of universal comparability is therefore sometimes called the abstraction of comparability. As a rule, the abstraction of comparability is a nontrivial hypothesis and is valid within the framework and on the basis of the main principles of theory.
M. M. NOVOSELOV [24–1047–1; updated]