Five different methods for a priori estimating bending strength of woo
d and wood composite specimens are compared in this paper. They are: (
I)edge-matching, (2) matching specimens by normal distribution, (3) ma
tching specimens by log-normal distribution, (4) simple linear regress
ion, and (5) multiple linear regression. It was found that the square
root of mean square error (RMSE) of percent difference (PD) of predict
ed modulus of rupture (MOR) is the key measure in comparing the five m
ethods. Multiple linear regression was found to be the best method to
predict MOR of a specimen in an edge-matched set. Finally, how to crea
te the prediction limits for mean MOR of a subgroup of specimens is di
scussed. The prediction limits for predicting MOR make it possible to
quantitatively determine the effect of various treatments of wood mate
rials.