formplot

Formplot is a term used in data visualization to describe a class of plots that emphasize the form or shape of a dataset or relationship, rather than focusing on precise pointwise values. It is not a single standardized plot type, but a family of representations designed to reveal structure such as modality, skew, and general trends by smoothing or outlining data distribution.

Common implementations include smoothing-based curves, density-based outlines, and distributional silhouettes. Examples include smoothed conditional means or curves produced by lowess or LOESS, kernel density estimates that form contours or ridges, and violin or other distribution plots that illustrate the shape of a variable’s distribution. In bivariate cases, formplots may use binned density, contour lines, or shaded regions to convey how the relationship between variables evolves across ranges or groups. Grouping by category, time, or other factors is often supported to compare forms across subsets of the data.

Formplots are commonly used in exploratory data analysis to quickly assess shape-related features such as multimodality, skewness, heteroscedasticity, and nonlinearity. They should be interpreted with attention to smoothing parameters, bandwidth, and sample size, which influence the perceived form. Limitations include potential oversmoothing that hides important features or misrepresenting uncertainty if confidence bands are not shown.

See also: density plots, violin plots, LOESS/LOWESS, kernel smoothing, scatter plots, time series plotting.