Comparisonbased

Comparisonbased is a term used to describe approaches that base outcomes on comparisons among items rather than on their absolute values. Often written as comparison-based or comparison based, it denotes a design philosophy or class of methods in which the relative ordering or preference between options drives the process.

In computer science, comparison-based algorithms determine order or structure by performing pairwise comparisons. This class includes well-known sorting algorithms such as quicksort, mergesort, and heapsort, which decide each step by comparing elements. A fundamental result is that any comparison-based sorting method requires at least Omega(n log n) comparisons in the worst case. Non-comparison-based sorts, such as counting sort or radix sort, can exceed this bound when the input domain permits it.

In decision analysis and data collection, comparison-based methods use pairwise judgments, rank order, or tournament-style elicitation to derive preferences, rankings, or outcomes. This approach is robust when absolute scales are unreliable or expensive to obtain, but it can be sensitive to inconsistent judgments and may require many comparisons to achieve a given accuracy.

Compared with absolute-measure approaches, comparison-based methods emphasize relative information, which can simplify modeling and improve interpretability in some contexts. The term is used across disciplines and often appears with hyphenation depending on the publication style.