R-value or rvalue may refer to: *

R-value (insulation) The ''R''-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat, in the context of construction. R-value is the temperature differen ...

in building engineering, the efficiency of insulation of a house * R-value (soils) in geotechnical engineering, the stability of soils and aggregates for pavement construction *

R-factor (crystallography) In crystallography, the R-factor (sometimes called residual factor or reliability factor or the R-value or RWork) is a measure of the disagreement between the crystallographic model and the experimental X-ray diffraction data - lower the R value lo ...

, a measure of the agreement between the crystallographic model and the diffraction data * ''R''₀ or ''R'' number, the

basic reproduction number In epidemiology, the basic reproduction number, or basic reproductive number (sometimes called basic reproduction ratio or basic reproductive rate), denoted R_0 (pronounced ''R nought'' or ''R zero''), of an infection is the expected number ...

in epidemiology * In computer science, a pure value which cannot be assigned to * In statistics, the

Pearson product-moment correlation coefficient In statistics, the Pearson correlation coefficient (PCC) is a correlation coefficient that measures linear correlation between two sets of data. It is the ratio between the covariance of two variables and the product of their standard deviation ...

, or simply ''correlation coefficient'' * In solid mechanics, the

Lankford coefficient The Lankford coefficient (also called Lankford value, R-value, or plastic strain ratio) is a measure of the plastic anisotropy of a rolled sheet metal. This scalar quantity is used extensively as an indicator of the formability of recrystallized ...

See also