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Abstract: To determine an equivalent dose (D e), the initial signal of the CW-OSL decay curve, supposedly dominated by the fast component, is used. Previous studies suggest that the resulting D e however, may be underestimated if thermally unstable medium or slow components are part of the initial decay curve. The D e(t) plot has the potential to reveal the “unclean” fast component. We have here studied quartz samples obtained from late Pleistocene floodplain deposits in the Lower Mississippi Valley (LMV), which show decreasing values of D e with increasing stimulation time. The deconvolution analysis of CW-OSL signals from these samples confirm the interpretation of the D e(t) plots. As a consequence, component-resolved values of D e were determined to obtain an accurate estimation of D e. Contrary to previous studies, our results indicate that the values of D e obtained with the initial signal are not underestimated for our samples containing a thermally unstable medium component. [Copyright &y& Elsevier]