We discuss a new measure to identify a small-scale dissipation region in collisionless magnetic reconnection. Traditionally, the dissipation region has been identified by the electron's nonidealness (E + v_e x B != 0). However, recent numerical results suggest that it may not accurately locate the reconnection site. In this talk, we propose an "electron-frame dissipation measure," the energy dissipation in the electron's frame, to identify the dissipation region. We discuss its relevance to the MHD dissipation and then we further test our measure using kinetic simulations. Implications for satellite observations are addressed, too.
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