Research Key word: #OnlineMarketplace #PointProcess #HawkesProcess #ExogenousFactors #EndogenousFactors 1. Overview of the research We analyzed listing data on Mercari to investigate the phenomenon of whether, when someone lists an item, others who see it also start listing items sequentially. We visualized the impact of external factors (such as news and seasonality) and internal factors (such as the chain reaction of listings). 2. The problem addressed: In online marketplaces, while a vast amount of price and product information can be collected, the detailed mechanisms of how transactions are induced remain unclear. To address this, we used Hawkes process analysis to illustrate market dynamics. 3. Research motivation and background: In Consumer-to-Consumer marketplaces like Mercari, understanding the mechanisms of how transactions occur and influence each other is crucial for developing market strategies and predicting transactions. 4. Results obtained: We developed a new estimation algorithm to capture the temporal impact of both exogenous and endogenous factors. When applied to Mercari's listing data, it was found that endogenous factors were present in certain categories such as "toys," "books," and "trading cards," where listings triggered further listings. On the other hand, in transactions across many categories, the impact of exogenous factors, specifically the emergency declarations during the COVID-19 pandemic, was observed. 5. Relationship with value exchange (analysis/creation) and the potential impact of that research on society: If this study can identify the timing when products are more likely to be listed, it could contribute to demand forecasting and the optimization of sales promotion strategies, thereby helping to improve the efficiency of both businesses and peer-to-peer transactions.
研究キーワード：#インターネット市場 #点過程 #Hawkes過程 #外生要因 #内生要因 1. 研究の概要 メルカリでの出品データを分析し，「誰かが出品すると，それを見た人も次々に出品するか？」という現象を検証し，外部要因（ニュース・季節性）と内部要因（出品の連鎖）の影響を可視化しました． 2. 取り組んだ問題 インターネット市場では価格や商品情報が膨大に収集可能ですが，取引がどのように誘引されるかの詳細なメカニズムは不明です．そのためHawkes過程解析を用い，市場の動態を示しました． 3. 研究のモチベーションと背景 メルカリのような個人間取引市場おいて，取引がどのように発生・影響し合うのか，そのメカニズムを理解することは，市場戦略の策定や取引予測に不可欠です． 4. 得られた結果 外生要因・内生要因それぞれの時間的な影響を捉えるための新たな推定アルゴリズムを開発しました。メルカリの出品データに適用した結果，「おもちゃ」「本」「トレーディングカード」など一部カテゴリで内生要因が確認され，出品が新たな出品を誘発することが明らかになりました．一方で，多くのカテゴリでの取引において，外生要因であるCOVID-19パンデミック下の緊急事態宣言の影響が見られました。 5. 価値交換（分析/生成）との関わりと社会的インパクト 本研究でどのようなタイミングで商品が出品されやすいか分かれば，需要予測や販売促進戦略の最適化に貢献し，企業や個人間取引の効率化に役立てられる可能性があります．
