Distribution of observed tSZE detection significance $\widehat{\zeta }$ and richness $\widehat{\lambda }$ as a function of redshift for the 698 galaxy clusters in the SPT sample that overlap the DES region. The solid line in the top figure shows the detection threshold for the three survey regions. In the bottom figure, the colored lines correspond to the ${\widehat{\lambda }}_{\min }(z)$ detection threshold for each survey.