Data-driven background estimation in CMS

The data-driven background measurement methods employed in the search for a light charged Higgs boson in the CMS experiment are reviewed. These backgrounds include the QCD multijet events and the EWK+$\mathrm{t}\bar{\mathrm{t}}$ events with a $\tau$ lepton in the $p_{\mathrm{T}}$, $\eta$ acceptance in the $\tau_{\mathrm{h}}$+jets final state analysis, and the misidentified $\tau$ background in the e$\tau_{\mathrm{h}}$ and $\mu\tau_{\mathrm{h}}$ final state analyses.