  We propose a method for setting limits that avoids excluding parameter values
for which the sensitivity falls below a specified threshold. These
"power-constrained" limits (PCL) address the issue that motivated the widely
used CLs procedure, but do so in a way that makes more transparent the
properties of the statistical test to which each value of the parameter is
subjected. A case of particular interest is for upper limits on parameters that
are proportional to the cross section of a process whose existence is not yet
established. The basic idea of the power constraint can easily be applied,
however, to other types of limits.
