臺灣博碩士論文加值系統

本文蒐集Foodpanda外送平台上之公開菜單資訊，研究2023年蛋荒期間餐飲業蛋類產品的供給情況。本文篩選出資料中六樣蛋類產品做為實驗組、兩樣飲品作為對照組，以雙重差分的個體固定效果模型比較蛋荒前中後期的價格差異。此外，本文亦區分出資料期間不曾下架產品及曾至少下架一次產品的兩類店家樣本，並分析兩者的迴歸結果差異。
研究結果顯示，蛋荒前至蛋荒高峰的價格變動與包含外送平台抽成的批發蛋價漲幅整體一致，並未出現過度加價的狀況。而在蛋荒結束後，蛋類產品售價並未隨著雞蛋缺口縮小及蛋價下跌回穩而回到無蛋荒下的水準，呈現出物價向下僵固的特性。此外，低價位、雞蛋佔成本比例高的產品存在部分店家以下架取代漲價的傾向，且重新上架後也較不會額外漲價，進而迴避了「凍跌不動漲」的向下僵固性，但此類店家的規模極小，對市場價格影響趨近於無。
而除控制固定效果及下架店家影響外，本文亦透過變更對照組、延長資料時間、下採樣及自助法等方式確保估計結果穩健性，但所有估計結果皆表明短期蛋荒衝擊存在長期的影響，顯示向下僵固性亦適用於短期的供給衝擊。

This study collects public menu information from the Foodpanda delivery platform to investigate the supply situation of egg-related products in the restaurant industry during the 2023 egg shortage. The research selects six egg-related products as the experimental group and two beverages as the control group, using a difference-in-differences model with individual fixed effects to compare price differences before, during, and after the egg shortage. Additionally, the study distinguishes between two sample groups of restaurants: those that never removed products from their menu during the data period and those that removed products at least once, analyzing the differences in regression results between the two.
The results show that the price changes from before the egg shortage to its peak are generally consistent with the wholesale egg price increase, including the delivery platform's commission, without evidence of excessive price hikes. After the egg shortage ended, the selling prices of egg-related products did not return to pre-shortage levels despite the narrowing egg supply gap and stabilizing egg prices, demonstrating downward price rigidity. Furthermore, there was a tendency among some restaurants, particularly for low-priced items with a high proportion of egg costs, to remove products from the menu rather than increase prices. When these items were relisted, they were less likely to have additional price increases, thus avoiding the "sticky downwards" phenomenon. However, such restaurants were very few in number, having negligible impact on market prices.
In addition to controlling for fixed effects and the impact of delisted items, the study ensures the robustness of its estimates through various methods, including changing the control group, extending the data period, under-sampling, and bootstrapping. All estimation results indicate that the short-term egg shortage had long-term effects, suggesting that downward price rigidity also applies to short-term supply shocks.

第一章 緒論 2
第二章 文獻回顧 5
第三章 資料說明 6
　第一節 產品與商家 6
　第二節 價格 7
　第三節 地區 12
　第四節 供應狀態 13
　第五節 小結 14
第四章 研究方法 15
　第一節 蛋荒效果 15
　第二節 店家產品固定效果 16
　第三節 異質蛋荒效果 17
　第四節 估計穩健度 17
　第五節 小結 18
第五章 研究結果 19
　第一節 固定效果 19
　第二節 異質效果 20
　第三節 折扣價 20
　第四節 價格上漲率 21
第六章 估計穩健度 24
　第一節 變更對照組 24
　第二節 下架店家影響 29
　第三節 個別產品異質效果下採樣 34
第七章 結論 37
參考文獻 38
附錄 39
　7月及8月蛋荒殘餘效果估計 39

Solórzano, Diego. (2024). Grab a bite? Prices in the food away from home industry during the COVID-19 pandemic. Journal of Economic Behavior & Organization, Elsevier, vol. 225(C), 435-464.
Cavallo, A. (2017). Are online & offline prices similar? Evidence from large multi-channel retailers. American Economic Review 107(1), 283-303.
Mankiw NG. (1985). Small Menu Costs & Large Business Cycles: A Macroeconomic Model of Monopoly. Quarterly Journal of Economics, 1985;100(May), 529-537.
Akerlof, George A & Yellen, Janet L. (1985). Can Small Deviations from Rationality Make Significant Differences to Economic Equilibria? American Economic Review, American Economic Association, 75(4), 708-720.
Zbaracki, M. J., Ritson, M., Levy, D., Dutta, S., & Bergen, M. (2004). Managerial and Customer Costs of Price Adjustment: Direct Evidence from Industrial Markets. The Review of Economics and Statistics, 86(2), 514–533.
Kehoe, Patrick & Midrigan, Virgiliu. (2015). Prices are sticky after all. Journal of Monetary Economics, Elsevier, 75(C), 35-53
Laurence, Ball., N., Gregory, Mankiw. (1994). Asymmetric Price Adjustment and Economic Fluctuations. The Economic Journal, 104(423), 247-261.
Eichenbaum, Martin, Nir Jaimovich, & Sergio Rebelo. (2011). Reference Prices, Costs, & Nominal Rigidities. American Economic Review, 101(1), 234-62.
Peltzman, Sam. (2000). Prices Rise Faster than They Fall. Journal of Political Economy, Vol. 108, No. 3 (June 2000), 466-502.
Abbas, S.K., & Lan, H. (2020). Commodity price pass-through & inflation regimes. Energy Economics, Elsevier, 92(C).
Kong, Xiangwen & Liu, Xiaoou. (2023). Delivery platform impacts on retail pass-through in the restaurant industry. 2023 Annual Meeting, July 23-25, Washington D.C. 335982, Agricultural & Applied Economics Association.