arXiv subjects

Veli Safak

Publications and source records attributed to Veli Safak.

5 recordsLinked to original sources

arXiv2023

Dual-Class Stocks: Can They Serve as Effective Predictors?

Kardemir Karabuk Iron Steel Industry Trade & Co. Inc., ranked as the 24th largest industrial company in Turkey, offers three distinct stocks listed on the Borsa Istanbul: KRDMA, KRDMB, and KRDMD. These stocks, sharing the sole difference in voting power, have exhibited significant price divergence over an extended period. This paper conducts an in-depth analysis of the divergence patterns observed in these three stock prices from January 2001 to July 2023. Additionally, it introduces an innovative training set selection rule tailored for LSTM models, incorporating a rolling training set, and demonstrates its significant predictive superiority over the conventional use of LSTM models with large training sets. Despite their strong correlation, the study found no compelling evidence supporting the efficiency of dual-class stocks as predictors of each other's performance.

q-fin.ST↗

arXiv2022

Elon Musk's Twitter Takeover: Politician Accounts

We provided quantitative data supporting significant changes between the time Twitter acceptance the offer on April 25 and the time the agreement was finalized on October 27. Republican politicians saw significant increases in their follower counts, while Democrat politicians saw significant decreases.

cs.SI↗

arXiv2021

Min-Mid-Max Scaling, Limits of Agreement, and Agreement Score

In this paper, I solve a 60-year old question posed by Cohen's seminal paper (1960) and offer an agreement measure centered around the chance-expected agreement while isolating marginally forced agreement and disagreement. To achieve this, I formulate the minimum feasible agreement given row and column marginals by devising a new algorithm that minimizes the sum of diagonals in contingency tables. Based on this result, I also formulate the lower limit of the most common agreement measure-Cohen's kappa. Finally, I study the lower limit of maximum feasible agreement and devise two statistics of distribution similarity for agreement analysis.

stat.ME↗

arXiv2020

Matching Multidimensional Types: Theory and Application

Becker (1973) presents a bilateral matching model in which scalar types describe agents. For this framework, he establishes the conditions under which positive sorting between agents' attributes is the unique market outcome. Becker's celebrated sorting result has been applied to address many economic questions. However, recent empirical studies in the fields of health, household, and labor economics suggest that agents have multiple outcome-relevant attributes. In this paper, I study a matching model with multidimensional types. I offer multidimensional generalizations of concordance and supermodularity to construct three multidimensional sorting patterns and two classes of multidimensional complementarities. For each of these sorting patterns, I identify the sufficient conditions which guarantee its optimality. In practice, we observe sorting patterns between observed attributes that are aggregated over unobserved characteristics. To reconcile theory with practice, I establish the link between production complementarities and the aggregated sorting patterns. Finally, I examine the relationship between agents' health status and their spouses' education levels among U.S. households within the framework for multidimensional matching markets. Preliminary analysis reveals a weak positive association between agents' health status and their spouses' education levels. This weak positive association is estimated to be a product of three factors: (a) an attraction between better-educated individuals, (b) an attraction between healthier individuals, and (c) a weak positive association between agents' health status and their education levels. The attraction channel suggests that the insurance risk associated with a two-person family plan is higher than the aggregate risk associated with two individual policies.

econ.EM↗

arXiv2020

Comparative Statics in Multicriteria Search Models

McCall (1970) examines the search behaviour of an infinitely-lived and risk-neutral job seeker maximizing her lifetime earnings by accepting or rejecting real-valued scalar wage offers. In practice, job offers have multiple attributes, and job seekers solve a multicriteria search problem. This paper presents a multicriteria search model and new comparative statics results.

econ.TH↗