Transversity at HERMES

A brief introduction to the transversity distribution function, denoted $\delta q$ or $h_1$, will be presented. Access to $h_1$ can be gained by measurement of Fourier moments of single-spin asymmetries in semi-inclusive production of mesons on a transversely polarized hydrogen target. Other transverse momentum dependent functions can also be accessed through various azimuthal moments. Preliminary results from HERMES will be presented. The experimental results from COMPASS will also be shown for comparison. An additional observable, the pion yield difference, will also be presented, as this observable has negligible contribution from vector meson decay.