Cochran-Armitage test for trend

The Cochran-Armitage test for trend is typically used in categorical data analysis when some categories are ordered. For example, doses can be ordered as 'low', 'medium', and 'high'. In some cases, the usual chi-square test may not be able to detect a trend, but the Cochran-Armitage test may be able to do so because a test statistic is chosen to reflect the anticipated trend.

The Cochran-Armitage test for trend can also be described as a method of directing chi-squared tests toward narrow alternatives. It is often used as a genotype-based test for candidate gene association.