论文标题
我们是否利用所有信息进行反事实分析?因素模型和特质校正的好处
Do We Exploit all Information for Counterfactual Analysis? Benefits of Factor Models and Idiosyncratic Correction
论文作者
论文摘要
最佳定价,即确定最大化给定产品的利润或收入的价格水平是零售业的重要任务。为了选择这样的数量,首先需要估算产品需求的价格弹性。回归方法通常由于混杂的影响和价格内生性而无法恢复这种弹性。因此,通常需要随机实验。但是,例如,弹性可能是高度异质性的,具体取决于商店的位置。由于随机分组经常发生在市政级别,因此标准差异方法方法也可能失败。可能的解决方案是基于方法的方法,以根据基于人工控制构建的反事实来衡量处理对单个(或仅几个)处理单位的影响。例如,对于治疗组中的每个城市,可以从未经处理的位置构建反事实。在本文中,我们采用一种新颖的高维统计方法来衡量价格变化对巴西主要零售商日常销售的影响。所提出的方法结合了主要成分(因子)和稀疏回归,从而导致了一种称为因子调整后的正规化方法进行治疗评估(\ texttt {farmTreat})。数据包括400多个市政当局的每日销售和五种不同产品的价格。被认为属于\ emph {Sweet and Candies}类别的产品,并且在2016年和2017年进行了实验。我们的结果证实了高度异质性的假设,在不同的城市中产生了非常不同的定价策略。
Optimal pricing, i.e., determining the price level that maximizes profit or revenue of a given product, is a vital task for the retail industry. To select such a quantity, one needs first to estimate the price elasticity from the product demand. Regression methods usually fail to recover such elasticities due to confounding effects and price endogeneity. Therefore, randomized experiments are typically required. However, elasticities can be highly heterogeneous depending on the location of stores, for example. As the randomization frequently occurs at the municipal level, standard difference-in-differences methods may also fail. Possible solutions are based on methodologies to measure the effects of treatments on a single (or just a few) treated unit(s) based on counterfactuals constructed from artificial controls. For example, for each city in the treatment group, a counterfactual may be constructed from the untreated locations. In this paper, we apply a novel high-dimensional statistical method to measure the effects of price changes on daily sales from a major retailer in Brazil. The proposed methodology combines principal components (factors) and sparse regressions, resulting in a method called Factor-Adjusted Regularized Method for Treatment evaluation (\texttt{FarmTreat}). The data consist of daily sales and prices of five different products over more than 400 municipalities. The products considered belong to the \emph{sweet and candies} category and experiments have been conducted over the years of 2016 and 2017. Our results confirm the hypothesis of a high degree of heterogeneity yielding very different pricing strategies over distinct municipalities.