高技术企业多元化战略对创新持续性的影响——动态能力的调节作用

基于资源基础理论和持续创新内生机制，利用435家高技术企业2010—2018年面板数据，对多元化战略对高技术企业创新持续性的影响进行探究。结果表明，产品多元化与创新持续性呈正U型关系，技术多元化对创新持续性具有正向促进作用，产品多元化与技术多元化协同效应对创新持续性具有负向影响；动态能力强化了产品多元化与创新持续性之间的正U型关系，并正向调节技术多元化与创新持续性之间的关系。在动态能力调节作用下，高技术企业产品多元化与技术多元化协同效应对创新持续性具有正向影响。     

Tourism,terrorism and political violence in Tunisia: Evidence from Markov-switching models

This study investigates the impact of terrorist attacks and political violence on the number of tourist arrivals and overnight stays in Tunisia. The dataset employed consists of monthly data that covers the period from January 2000 to September 2016, which includes several political and terrorist attacks in Tunisia and the region. Empirically, we investigate the true data generating process (DGP) of these two proxies of tourism activity by accounting for four statistical properties that characterize these series: (1) seasonality, (2) unit roots, (3) breaks, and (4) long memory behavior.Our empirical findings show strong evidence of stationarity, five breaks in the tourist arrival time series and spurious long memory behavior. By estimating a 3-state Markov switching model consisting of the mean, trend, and variance, we find that the Tunisian Jasmine revolution and two recent terrorist attacks, one at the Bardo National Museum on March 18, 2015 and the other at the tourist resort at Port El Kantaoui, Sousse on June 26, 2015, played an important role in influencing the tourism activity of the country. Our empirical findings show also that local shocks have a more important impact than international shocks in influencing tourism activity. Interestingly, we find that the effects of terrorist shocks have a long duration compared to political violence shocks. Several security, marketing, and economic policies have been proposed and discussed in the paper.     

Persistence of Price–Cost Margin and Technical Efficiency in the Indonesian Food and Beverage Industry

Abstract

This research investigates the persistence of price–cost margin (PCM) and technical efficiency (TE) of firms and the relation between these two factors in 44 subsectors of the Indonesian food and beverage industry in the period 1980–2014. Data envelopment analysis with a bootstrapping approach is applied to estimate TE. An autoregressive model, accounting for endogeneity, is applied to estimate the persistence coefficients of PCM and TE. A cross-sectional regression model is also applied to estimate the relation between the persistence of the PCM and the persistence of TE. The results show that for these food and beverage firms, high PCM and low TE persist. Furthermore, the persistence of PCM negatively affects the persistence of TE in the industry.     

Gender Diversity Index. Measuring persistence

This paper deals with the analysis of the Gender Diversity Index (GDI), which is an Index developed by Solactive AG and is calculated and distributed by this provider. The index tracks the performance of developed world companies that are successfully working towards gender diversity as part of their CSR (Corporate Social Responsibility) strategy, and we measure its degree of persistence by using fractional integration or I(d) techniques. Using daily data from 8 December 2010 until 16 December 2020, the results indicate that the series is highly persistent with an order of integration lower than, though very close to 1. However, an interesting result is obtained by estimating d recursively across subsamples. The differencing parameter moves around 0.92 until 23 March 2020, with the series displaying a very small degree of mean reversion behaviour until that date. After that period, however, we observe an increase in the estimate of d, which stabilizes around 0.97 after 5 May 2020, though now the series presents evidence of a lack of mean reversion, with the shock having a permanent effect on the series. Thus, it seems that the sanitary crisis due to Covid-19 has had a clear effect in the degree of persistence of the GDI data.     

依赖性与嵌入性：产学研合作创新持续性研究

作为合作创新的重要形式，产学研合作创新为资源整合、产业优化与经济发展作出了重要贡献。基于国家重点产业专利信息服务平台，以我国电子元器件产业产学研合作发明专利为数据来源，采用Logistic回归模型实证检验依赖性与嵌入性对产学研合作创新持续性的影响。结果表明：在依赖性的3个要素中，地理邻近性对产学研合作创新持续性不具有显著影响，知识相似性和身份相似性均对产学研合作创新持续性具有显著正向影响；在嵌入性的3个要素中，结构嵌入性对产学研合作创新持续性不具有显著影响，关系嵌入性和位置嵌入性均对产学研合作创新持续性具有显著正向影响。但是，当所有因素同时进入回归模型时，只有知识相似性和关系嵌入性对产学研合作创新持续性具有显著正向影响，身份相似性和位置嵌入性的影响不再显著。     

Generalized runs tests to detect randomness in hedge funds returns

The major contribution of this paper is to make use of generalized runs tests (Cho and White, 2011) to analyze the randomness, i.e. the lack of persistence, in both absolute and relative returns of hedge funds. We find that about 42% of the HFR universe exhibit iid absolute returns over the period spanning 2000 to 2012. These funds are mainly found in proportions within the Macro and Equity Hedge strategies. A similar result holds for relative returns. We also find that funds having non-iid returns often exhibit ARCH effects and structural breaks, with largest breaks located within financial crises. Also, only a small percentage displays persistence in their relative performance, 8.2% to 16.7% of the universe, mainly found in proportions within the Relative Value and Event-Driven strategies. The robustness of results is challenged by implementing the tests on a crisis-free period. We find similar results for absolute returns. For relative ones, differences appear across strategies and benchmarks, but still both ARCH and breaks are present. Our work contributes to the hedge fund literature in terms of methodology, portfolio allocation, and performance measurement.     

Comparative persistence and adherence with newer anti-hyperglycemic agents to treat patients with type 2 diabetes in the United States

Objectives: Non-adherence and non-persistence to anti-hyperglycemic agents are associated with worse clinical and economic outcomes in patients with type 2 diabetes. This study evaluated treatment persistence and adherence across newer anti-hyperglycemic agents (canagliflozin, dapagliflozin, sitagliptin, saxagliptin, linagliptin, liraglutide, or exenatide).

Methods: This retrospective cohort study of Truven Health Analytics Marketscan databases included adult patients with type 2 diabetes whose first pharmacy claim for a newer anti-hyperglycemic agent was between February 1, 2014 and July 31, 2014. Treatment persistence and adherence were assessed for 12 months after the first claim (post-index). Persistence was defined as no gap ≥90 days between the end of one pharmacy claim and the start of the next pharmacy claim post-index. Adherence used two definitions: proportion of days covered (PDC) and medication possession ratio (MPR). Multivariable analyses of non-persistence (hazard ratios) and adherence (odds ratios) were adjusted for baseline demographics, drug cost, clinical characteristics, and other anti-hyperglycemic agents.

Results: A total of 11,961 patients met all study selection criteria. Persistence rates at 12 months were significantly greater (p?p?=?0.83; PDC?=?0.79) and canagliflozin 300?mg (MPR?=?0.92; PDC?=?0.81) were greater than for the other index anti-hyperglycemic agents (MPR?=?0.33–0.75; PDC?=?0.33–0.72). Consistent results for treatment persistence and adherence were observed in multivariable analyses that were adjusted baseline characteristics.

Conclusions: Canagliflozin was associated with better treatment persistence and treatment adherence compared with other anti-hyperglycemic agents in real-world settings.     

中国通货膨胀的动态特征研究

现有测度通胀惯性的常用模型是仅含自身滞后因子的自回归模型,该模型不能有效反映通胀预期和波动性对通胀惯性的影响。本文在自回归模型基础上,构建了一个包含通胀惯性、学习型预期和波动性特征的通胀动态模型。该动态模型从均值和波动项两个方面反映了我国通胀水平的动态变化趋势和特征。针对上述模型不能有效反映通胀状态体制变化的缺点,本文还引入Markov机制转换模型来测度我国通胀水平的状态转移特征。利用分位数回归方法下的自回归模型、本文构建的通胀动态模型以及Markov机制转化模型实证研究了我国通胀的动态特征。分析表明:我国通胀水平具有较强的惯性特征;通胀惯性的形成机理比较复杂,学习型预期只能部分解释通胀惯性;通胀水平的状态转移时间比较长;通胀水平与其波动性有着正向的关系。     

Contract length heterogeneity and the persistence of monetary shocks in a dynamic generalized Taylor economy

We develop the generalized Taylor economy (GTE) in which there are many sectors with overlapping contracts of different lengths. In economies with the same average contract length, monetary shocks will be more persistent when longer contracts are present. Using the Bils–Klenow distribution of contract lengths, we find that the corresponding GTE tracks the U.S. data well. When we choose a GTE with the same distribution of completed contract lengths as the Calvo, the economies behave in a similar manner.