Redshift distribution of events for various surveys. For the SDSS and SNLS, the distributions sketch the total sample of spectroscopically identified events eventually entering the Hubble diagram. “DES 5” and “DES 10” refer respectively to the “hybrid-5” and “hybrid-10” strategies studied in Bernstein et al. (2012), where the baseline is hybrid-10. “LSST-SHALLOW”, “LSST-DDF” and “DESIRE” refer to the three prongs studied in this proposal.