Ympyräkaavioon

Ympyräkaavio, also known as a pie chart, is a circular statistical graphic divided into slices to illustrate numerical proportion. Each slice's arc length is proportional to the quantity it represents. For example, a slice representing 50% of the data would occupy half of the circle. Ympyräkaaviot are commonly used to show how a whole is divided into parts and are particularly effective when comparing a small number of categories.

The origin of the ympyräkaavio is attributed to William Playfair, who introduced it in his 1801 book "The Statistical Breviary". Playfair, a Scottish engineer and political economist, used the chart to display data in a visually accessible manner. While simple in concept, the ympyräkaavio can become cluttered and difficult to interpret if too many categories are included. Experts generally recommend using no more than five to seven slices for optimal clarity.

When creating a ympyräkaavio, it is important to ensure that the data represents parts of a whole. The sum of all slices should equal 100%. Color coding is often used to distinguish between different categories, and labels or legends are typically provided to identify each slice. Although widely recognized, ympyräkaaviot are sometimes criticized for making it difficult to compare the sizes of similar slices accurately. Bar charts or other types of graphs may be more suitable in such instances.