An asymptotic expression is given for the $\log$ error probability of a sequential test based on a random walk. This may be used to compute limiting relative efficiencies of such tests. The results are illustrated for the one-sided normal testing problem with an asymptotic Bayes test due to Schwarz. Some numerical comparisons are given for five sequential tests of a normal mean.
"Asymptotic Efficiencies of Sequential Tests II." Ann. Statist. 6 (4) 813 - 819, July, 1978. https://doi.org/10.1214/aos/1176344254