  In a 1961 paper, Box and Hunter defined the resolution of a regular
fractional factorial design as a measure of the amount of aliasing in the
fraction. They also indicated that the maximum resolution is equal to the
minimum length of a defining word. The idea of a wordlength pattern has now
been extended to nonregular designs by various authors, who show that the
minimum generalized wordlength equals the maximum strength plus 1.
  Minimum generalized wordlength is often taken as the definition of
resolution. However, Box and Hunter's original definition, which does not
depend on wordlength, can be extended to nonregular designs if they are simple.
The purpose of this paper is to prove that the maximum Box-Hunter resolution
does equal the maximum strength plus 1, and therefore equals the minimum
generalized wordlength. Other approaches to resolution are briefly discussed.
