The device and method for measuring the effect of soiling on a photovoltaic device includes a device in which a photovoltaic device (reference solar cell, solar cells, PV module, etc.) may be shifted between partially and fully enclosed compartments in quick succession for measurements of the same device (1) when directly exposed to illumination or solar radiation; (2) when placed under a glass or transparent cover maintained cleared or cleaned of soil; and (3) when placed under glass or transparent cover left exposed to natural outdoor soiling, or attenuated using simulated soil that is not periodically cleaned. The measurements may be of short circuit current (Isc), maximum power (Pmax), or other electrical parameter conventionally used to evaluate performance of the photovoltaic device. A soiling ratio calculated as: SR Pmax = 1 - P max ⁢ ⁢ 2 - P max ⁢ ⁢ 3 P max ⁢ ⁢ 1 or calculated as: SR Isc = 1 - I sc ⁢ ⁢ 2 - I sc ⁢ ⁢ 3 I sc ⁢ ⁢ 1 may be used to compare or monitor performance of the photovoltaic device between measurement cycles.