R-value

R-value or rvalue may refer to:
 * R-value (insulation) 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), a measure of the agreement between the crystallographic model and the diffraction data
 * R0 or R number, the basic reproduction number in epidemiology
 * In computer science, a pure value which cannot be assigned to
 * In statistics, the Pearson product-moment correlation coefficient, or simply correlation coefficient
 * In solid mechanics, the Lankford coefficient