  We propose a formal method to declare that findings from a primary study have
been replicated in a follow-up study. Our proposal is appropriate for primary
studies that involve large-scale searches for rare true positives (i.e. needles
in a haystack). Our proposal assigns an $r$-value to each finding; this is the
lowest false discovery rate at which the finding can be called replicated.
Examples are given and software is available.
