Three Corrected Score Tests for Generalized Linear Models with Dispersion Covariates

We develop three corrected score tests for generalized linear models with dispersion covariates, thus generalizing the results of Cordeiro , Ferrari and Paula (1993) and Cribari-Neto and Ferrari (1995) . We present, in matrix notation, general formulae for the coefficients which define the corrected statistics. The formulae only require simple operations on matrices and can be used to obtain analytically closed-form corrections for score test statistics in a variety of special generalized linear models with dispersion covariates. They also have advantages for numerical purposes since our formulae are readily computable using a language supporting numerical linear algebra. Two examples, namely, iid sampling without covariates on the mean or dispersion parameter oand one-way classification models, are given. We also present some simulations where the three corrected tests perform better than the usual score test, the likelihood ratio test and its Bartlett corrected version. Finally, we present a numerical example for a data set discussed by Simonoff and Tsai (1994) .     

Fiscal stabilizations: When do they work and why

This paper studies the determinants and channels through which fiscal contractions influence the dynamics of the debt-to-GDP ratio and GDP growth. Using data from a panel of OECD countries, the paper shows that the success of fiscal adjustments in decreasing the debt-to-GDP ratio depends on the size of the fiscal contraction and less on its composition. The rate of growth of output matters too, but higher GDP growth does not drive the success of a fiscal stabilization. In contrast, whether a fiscal adjustment is expansionary depends largely on the composition of the fiscal maneuvre. In particular, stabilizations implemented by cutting public spending lead to higher GDP growth rates. The effects of the composition on growth work mostly through the labor market rather than through agents’ expectations of future fiscal policy. Finally, the evidence suggests that successful and expansionary fiscal contractions are not the result of accompanying expansionary monetary policy or exchange rate devaluations.     

Incubation matters: Measuring the effect of business incubators on the innovation performance of start‐ups

This article explores the role of business incubators on the innovation performance of start‐ups; in addition, we also investigate how the incubation effect moderates other important factors driving their innovation performance. The empirical evidence comes from a sample of firms located in Northern Italy belonging to the manufacturing (mechanical engineering firms) and service sectors (knowledge‐intensive business services). The results suggest that the incubation effect is very important in shaping the innovation performance of new ventures (measured as a percentage of sales of new‐to‐market innovations). Moreover, it positively moderates the impact of (1) the internal technical capabilities and (2) the adoption of a limited portfolio of collaborations for innovation.     

Cost-effectiveness of dedicated dietitians for hyperphosphatemia management among hemodialysis patients in Lebanon: results from the Nutrition Education for Management of Osteodystrophy trial

Aim: To assess the cost-effectiveness of nutrition education by dedicated dietitians (DD) for hyperphosphatemia management among hemodialysis patients.

Materials and methods: This was a trial-based economic evaluation in 12 Lebanese hospital-based units. In total, 545 prevalent patients were cluster randomized to DD, trained hospital dietitian (THD), and existing practice (EP) groups. During Phase I (6 months), DD (n?=?116) received intensive education by DD trained on renal nutrition, THD (n?=?299) received care from trained hospital dietitians, and EP (n?=?130) received usual care from untrained hospital dietitians. Patients were followed-up during Phase II (6 months).

Results: At baseline, EP had the lowest weekly hemodialysis time, and DD had the highest serum phosphorus and malnutrition-inflammation score. The additional costs of the intervention were low compared with the societal costs (DD: $76.7, $21,007.7; EP: $4.6, $18,675.4; THD: $17.4, $20,078.6, respectively). Between Phases I and II, DD showed the greatest decline in services use and societal costs (DD: –$2,364.0; EP: –$1,727.7; THD: –$1,105.7). At endline, DD experienced the highest decrease in adjusted serum phosphorus (DD: –0.32; EP: +0.16; THD: +0.04?mg/dL), no difference in quality-adjusted life-years (QALY), and the highest societal costs. DD had a cost-effectiveness ratio of $7,853.6 per 1?mg decrease in phosphorus, compared with EP; and was dominated by THD. Regarding QALY, DD was dominated by EP and THD. The results were sensitive to changes in key parameters.

Limitations: The analysis depended on numerous assumptions. Interpreting the results is limited by the significant baseline differences in key parameters, suggestive of higher baseline societal costs in DD.

Conclusions: DD yielded the greatest effectiveness and decrease in societal costs, but did not affect QALY. Regarding serum phosphorus, DD was likely to be cost-effective compared with EP, but had a low cost-effectiveness probability compared with THD. Regarding QALY, DD was not likely to be cost-effective. Assessing the long-term cost-effectiveness of DD, on similar groups, is recommended.     

Are EU trade preferences really effective? An impact evaluation assessment of the Southern Mediterranean Countries’ case

This work assesses the causal impact of the EU trade preferences granted to the Southern Mediterranean Countries (SMCs) in agriculture and fishery products over the period 2004–2014. It overcomes some of the weaknesses of previous assessments and presents several methodological improvements. Firstly, it relies on a continuous treatment – i.e. preferential margins – to capture the ‘average treatment effect’ of trade preferences, rather than on a binary treatment based on dummy variables. Secondly, it uses highly disaggregated data at sectoral level in order to evaluate properly the preferential treatment. Thirdly, it applies a non-parametric matching technique for continuous treatment – specifically, a generalized propensity score matching. The results show, on the one hand, that the impact of the EU preferences is positive and significant on SMCs trade and is better evaluated using impact evaluation techniques. On the other hand, they demonstrate that the relationship between preferences and trade flows is asymmetric and warn against the risk of providing too much of a good thing. These results raise important issues for policy-making. First, they demonstrate that raising the level of preferences is not the solution to foster the SMCs trade towards EU. Second, that the policy-makers should put more emphasis on complementary factors other than trade barriers.     

Investigating the moderating effect of information sources on cruise tourist behaviour in a port of call

The aim of the study is to examine how destination knowledge acquired by cruisers through different information sources (online versus others) can moderate destination image formation and the relationship of image–satisfaction–behavioural intentions in a port of call. A multiple group analysis with partial least square method was carried out using data collected from a major tourism destination in Spain: Valencia. The findings revealed knowledge acquired through different information sources is a moderator of the image–satisfaction and satisfaction–behavioural intention relationships. The destination image formation is also significantly different from one group to the other. The findings of this study have a number of practical implications.     

A Comparison of Consensus and BVAR Macroeconomic Forecasts

This paper provides a one-month-ahead, macroeconomic, Bayesian Vector Autoregressive (BVAR) forecasting approach that offers several advantages over conventional short-term forecasting procedures. In particular, it produces more accurate forecasts than the Bloomberg consensus forecasts, on average, for 20 major macroeconomic variables. In addition to a quantitative comparison of BVAR and Bloomberg consensus forecast, the paper focuses on five important areas of macroeconomic forecasting: the role of short-term macroeconomic forecasting, the importance of a robust forecasting approach, the importance of timing of data releases, forecast evaluation criteria, and the importance of changing model specifications as conditions warrant.     

Kognitive Dissonanz »Revisited«

Using the theory of cognitive dissonance, this study investigates whether users of an online magazine prefer contents that agrees to their attitudes to political issues. In contrast to earlier studies, dissonance is defined issue-specifically rather than by party identification. Moreover, personal relevance is also included. In a two-step data collection, attitudes and relevance assessments were measured first. Participants were asked in a second session to look at an online magazine. Background software recorded the selection of and the time spent with specific contents as participants looked at the magazine. Results show that users spent more time with attitude-consistent information. This was, however, mostly due to persons who had rated issue relevance high. Users with low or moderate rating for issue relevance spent significantly less time with attitude-consistent content and significantly more time with attitude-inconsistent information, as compared with users with high relevance ratings. The influence of issue relevance is discussed as an explanation of contradictory results on cognitive dissonance and media use.     

Trade Costs in Bilateral Trade Flows: Heterogeneity and Zeroes in Structural Gravity Models

This paper contributes to the explanation of international trade flows with structural gravity models taking heterogeneity and excess zeroes into account. We introduce a more general hypothesis on the structure of trade costs in Helpman et al. (The Quarterly Journal of Economics, 2008; 123 , 2, 441) theoretical model that is capable of explaining over‐dispersion in trade data. Zero‐inflated negative binomial models are considered to analyse the impact of trade costs, measured in terms of geographical distance and contiguity effects. An analysis related to a sample of 37 countries' trade flows, with heterogeneous effects across sectors and trade‐integrated areas, such as APEC and EU, is presented. The size of exporting and destination economies and cultural and institutional factors are considered as influencing both the extensive and the intensive margin of trade.