Erratum to: Behav Res

10.3758/s13428-011-0111-y

Published Vol 43 No 4, pp. 971–980

The second equation on page 978 erroneously contained a minus sign at the start of the right side of the equation. The correct equation is

$$ \rho =\frac{rt+4}{t-3} $$

The error did not affect any reported results because all statistical analyses used the correct equation.