Kattavuus

Kattavuus is a term used in Finnish to describe the extent to which something covers or reaches a defined target. In statistics and research, it refers to population coverage—the proportion of the defined population that is included in a study or observation. Coverage errors occur when parts of the target population are not included (undercoverage) or when non-target units are included (overcoverage). In other fields the term has domain-specific meanings but retains the core idea of breadth or reach.

In public health, vaccination coverage denotes the share of a target group that has received a vaccine, and it is a key metric for assessing program performance, planning, and herd immunity thresholds. In telecommunications and geography, geographic or signal coverage describes the area where service is available and of acceptable quality, influenced by infrastructure, terrain, and population density. Coverage is often visualized with maps and statistics to guide infrastructure investment and policy.

In data quality and software testing, test coverage measures the extent to which the codebase or product features are exercised by tests; higher coverage can indicate fewer untested parts, though it does not guarantee defect absence. In media studies, coverage refers to how extensively a topic is reported by outlets, affecting public awareness and perception.

Measuring kattavuus typically involves calculating a proportion, such as covered units divided by total target units, while accounting for sampling design and potential measurement error. Limitations include bias, changes over time, and the dynamic nature of target populations. Understanding kattavuus supports effective planning, evaluation, and resource allocation across health, technology, data analysis, and media disciplines.