We propose a method for estimating first passage time densities of
one-dimensional diffusions via Monte Carlo simulation. Our approach involves a
representation of the first passage time density as expectation of a functional
of the three-dimensional Brownian bridge. As the latter process can be
simulated exactly, our method leads to almost unbiased estimators. Furthermore,
since the density is estimated directly, a convergence of order 1/N,
where N is the sample size, is achieved, the last being in sharp contrast to
the slower non-parametric rates achieved by kernel smoothing of cumulative
distribution functions.Comment: 14 pages, 2 figure