At other times, the ration can only be estimated by the beneficiary, like a factory for which energy is to be rationed. In such cases, a mechanism is needed to discourage misreporting the needs or wants (i.e. to meet strategy-proofness.) Suppose every participant reports an ideal ration. For so-called uniform rationing, each ration is set to the minimum of the participant's ideal ration and a cap, the cap being determined so that the sum of the rations equals the amount available. So, loosely speaking, the participant asking least will be served first. This mechanism is strategy-proof, avoids unnecessary waste (Pareto optimality) and equally treats equals (anonymity.) In fact, it is the only such mechanism. (Anonymity in this statement can be replaced by envyfreeness.) For the redistribution of scarce goods to demanders by suppliers, see non-monetary microeconomies.