  What else can be said about star formation rate indicators that has not been
said already many times over? The `coming of age' of large ground-based surveys
and the unprecedented sensitivity, angular resolution and/or field-of-view of
infrared and ultraviolet space missions have provided extensive, homogeneous
data on both nearby and distant galaxies, which have been used to further our
understanding of the strengths and pitfalls of many common star formation rate
indicators. The synergy between these surveys has also enabled the calibration
of indicators for use on scales that are comparable to those of star-forming
regions, thus much smaller than an entire galaxy. These are being used to
investigate star formation processes at the sub-galactic scale. I review
progress in the field over the past decade or so.
