Logarithm (base 10) of Bayes factor comparing models with 1 vs. 0 (blue) and 2 vs. 1 (orange) planets computed on 1000 simulated RV time series (black points). In abscissa the Bayes factor is computed with correct priors. In ordinate, the Bayes factor is computed with identical priors except on period, where the prior width is log-uniform on [1.5, 10 000] days instead of [1.5, 100], The red line represents a linear regression.