There has been considerable interest in random projections, an approximate algorithm for estimating distances between pairs of points in a high-dimensional vector space. Let A ∈ R n×D be our n points in D dimensions. The method multiplies A by a random matrix R ∈ R D×k , reducing the D dimensions down to just k for speeding up the computation. R typically consists of entries of standard normal N (0, 1). It is well known that random projections preserve pairwise distances (in the expectation). Achlioptas proposed sparse random projections by replacing the N (0, 1) entries in R with entries in {−1, 0, 1} with probabilities { }, achieving a threefold speedup in processing time.We recommend using R of entries in {−1, 0, 1} with probabilities {} for achieving a significant √ Dfold speedup, with little loss in accuracy.