A posteriori ratemaking using bivariate Poisson models

Recently, different bivariate Poisson regression models have been used in the actuarial literature to make an a priori ratemaking taking into account the dependence between two types of claims. A natural extension for these models is to consider a posteriori ratemaking (i.e. experience rating models) that also relaxes the independence assumption. We introduce here two bivariate experience rating models that integrate the a priori ratemaking based on the bivariate Poisson regression models, extending the existing literature for the univariate case to the bivariate case. These bivariate experience rating models are applied to an automobile insurance claims data-set to analyse the consequences for posterior premiums when the independence assumption is relaxed. The main finding is that the a posteriori risk factors obtained with the bivariate experience rating models are significantly lower than those factors derived under the independence assumption.     

Longevity and adjustment in pension annuities,with application to Finland

The aim of this paper is twofold. First, the improvement in adult mortality in Finland is studied. Lee-Carter (LC) Poisson log-bilinear model is used for mortality forecasting. Secondly, the paper studies how the pension annuities are adjusted to unexpected mortality pattern. A formula for funded plan is proposed. Application is made with Finnish mortality rates predicted using the LC model.     

On finite-time ruin probabilities for classical risk models

Abstract

Generally, the return of premiums without interest or with simple interest is provided for. It might, however, be worth while to notice that less complicated formulre are needed for the return of premiums with compound interest.     

Goodness-of-fit tests for Poisson count time series based on the Stein–Chen identity

To test the null hypothesis of a Poisson marginal distribution, test statistics based on the Stein–Chen identity are proposed. For a wide class of Poisson count time series, the asymptotic distribution of different types of Stein–Chen statistics is derived, also if multiple statistics are jointly applied. The performance of the tests is analyzed with simulations, as well as the question which Stein–Chen functions should be used for which alternative. Illustrative data examples are presented, and possible extensions of the novel Stein–Chen approach are discussed as well.     

Election cycles in mining licensing: theory and evidence from Albania

Most of the literature on political business and budgetary cycles (PBBC) has focused on fiscal and monetary policy variables in advanced-country contexts. We extend this literature by investigating political cycle effects in a non-monetary, non-fiscal policy regime (the allocation of mining licences) in a transition country context. We propose a model of mining licensing that allows for corruption and for both supply and demand effects to determine the outcome. We then estimate this model using time-series data from post-communist Albania. Relying on a dynamic Poisson model, we find evidence of both opportunistic and partisan effects. Based on our theory, we suggest a corruption interpretation of political cycles in non-fiscal/non-monetary variables. This interpretation, we suggest, may be more applicable to the context of developing and transition countries. Our study raises important questions about the unintended (and often pernicious) effects of transition politics on economic regulation and economic performance in post-socialist economies.     

Composing tweets to increase retweets

Brands tweet not only to communicate with followers but also to reach large audiences rapidly when the tweets are retweeted by the followers. People however will retweet only if they recognize within a few seconds that the tweet is on an interesting topic. Brands therefore need insights into how to compose tweets to facilitate topic recognition even when they are just scanned. This is the issue that we address in this research. Specifically, drawing on findings in psycholinguistics, we empirically investigate if tweets composed such that they include more topic-related words that are located closer to the start get more retweets. Results from an investigation of sales-promotional tweets by sixty brands in four categories indicate that tweets that are composed as above do get more retweets. We repeat the investigation using tweets on several other topics from a natural experiment that generated pairs of tweets where each pair is on the same topic but each tweet in the pair is composed differently. This investigation reconfirms the findings from the analysis of retweets of sales-promotional tweets. We conclude by presenting an approach for how social media managers can compose tweets based on our findings.     

Kosovo – EU trade relations: a dynamic panel poisson approach

To inform policymaking following trade liberalization between Kosovo and the EU within the framework of the Stabilisation and Association Agreement (SAA), we specify a gravity model to investigate Kosovo’s trade in goods with 28 EU countries over the period 2005–2013. We reconcile competing methodological requirements by using a dynamic Poisson approach to estimation. Together, persistent trade patterns and an unfavourable combination of demand and supply elasticities suggest that trade liberalization in isolation is not sufficient to promote exports but may need to be incorporated within a wider policy and institutional framework. In addition, our findings suggest that trade costs should be a particular focus for policy: distance has a big negative influence on Kosovo’s exports to EU countries; while diaspora communities promote Kosovo’s exports to EU markets, most likely because they offset trade costs.     

Is bootstrap really helpful in point process statistics?

There are some papers which describe the use of bootstrap techniques in point process statistics. The aim of the present paper is to show that the form in which bootstrap is used there is dubious. In case of variance estimation of pair correlation function estimators the used bootstrap techniques lead to results which can be obtained simpler without simulation; furthermore, they differ from the desired results. The problem to obtain confidence regions for the intensity function of inhomogeneous Poisson processes can be easily solved without bootstrap techniques. Received: June 1999     

On a study of the exponential and Poisson characteristics of the Poisson process

Based on the exponential and Poisson characteristics of the Poisson process, in this work we present some characterizations of the Poisson process as a renewal process. More precisely, let γ_t be the residual life at time t of the renewal process A={A(t),t≥0 }, under suitable condition, we prove that if Var(γ_t)=E ² (γ_t),∀t≥0, then A is a Poisson process. Secondly, we show that if Var (A(t)) is proportional to E (A(t)), then A is a Poisson process also, and Var (A(t))=E (A(t)). Received: August 1999