企業永續經營之根本在提供顧客所需產品或服務，並賺取合理的利潤。故如何精確地預測並滿足顧客需求，為企業首要之工作。一般而言，需求預測的精確度和投資在預測上的人力及金錢成正相關。本文經由數學模型推導，探討單期季節性商品的決策者應如何訂定需求預測的預算。結果發現需求預測預算具有一上限金額，此一金額代表需求預測所能產生之最大可能利益(即完全資訊期望價值)。接著藉由敏感度分析，本文並探討模型中售價及各項成本因素對此完全資訊期望價值之影響。

The survival of a business is based on how to predict and satisfy customer's needs. In general, the precision of demand forecasting is closely related to budget invested in forecasting and the nature of demand. In this paper, we develop a single-product single-period model to study how to determine the appropriate amount of budget spent in forecasting. We find there is an upper bound of the budget and is denoted as expected value of perfect information(EVPI). Finally, we discuss the relation between EVPI and model parameters in the sensitivity analysis.