An individual measure of relative survival

Summary.  Relative survival techniques are used to compare survival experience in a study cohort with that expected if background population rates apply. The techniques are especially useful when cause-specific death information is not accurate or not available as they provide a measure of excess mortality in a group of patients with a certain disease. Whereas these methods are based on group comparisons, we present here a transformation approach which instead gives for each individual an outcome measure relative to the appropriate background population. The new outcome measure is easily interpreted and can be analysed by using standard survival analysis techniques. It provides additional information on relative survival and gives new options in regression analysis. For example, one can estimate the proportion of patients who survived longer than a given percentile of the respective general population or compare survival experience of individuals while accounting for the population differences. The regression models for the new outcome measure are different from existing models, thus providing new possibilities in analysing relative survival data. One distinctive feature of our approach is that we adjust for expected survival before modelling. The paper is motivated by a study into the survival of patients after acute myocardial infarction.     

Financial frictions and indebtedness of Balkan firms: A comparison with Mediterranean and Central European countries

Using a large database of financial data for non-financial corporations, we study the process of debt accumulation and its influence on liquidity through the boom-bust-recovery regimes (2006–2010) in the Balkan countries and benchmark this against the Mediterranean and Central European countries. The domestic amplification effects (through the financial accelerator and collateral pricing) of both the capital surge from developed EU countries at the onset of the crisis and the capital reversal afterwards are the focus of the analysis. We show that domestic generators and amplificators of the crisis have much larger effects in the Balkan countries than in the Mediterranean countries, not to mention the countries of Central Europe. In the boom period, the financial accelerator was several times stronger in the Balkan countries than in the Mediterranean and Central European countries. In the bust and recovery periods, however, the direct effects of the financial accelerator declined, but the indirect effects increased considerably due to liquidity squeezes and contagion, especially strong were corresponding intercompany debt effects. In the Balkan countries, these effects in the bust and recovery periods were at least 50% larger than in the Mediterranean and Central European countries. Higher crisis costs in the Balkan countries, relative to the benchmark regions, could be attributed to the late integration of these economies into international financial and trade flows, weak institutions of financial intermediation, and inexperienced regulators; however, the importance of the contribution of misguided EU convergence doctrine cannot be ignored. Lessons for improving macromanagement in EU periphery countries are suggested.     

On a measure of information gain for regression models in survival analysis

Papers dealing with measures of predictive power in survival analysis have seen their independence of censoring, or their estimates being unbiased under censoring, as the most important property. We argue that this property has been wrongly understood. Discussing the so-called measure of information gain, we point out that we cannot have unbiased estimates if all values, greater than a given time τ, are censored. This is due to the fact that censoring before τ has a different effect than censoring after τ. Such τ is often introduced by design of a study. Independence can only be achieved under the assumption of the model being valid after τ, which is impossible to verify. But if one is willing to make such an assumption, we suggest using multiple imputation to obtain a consistent estimate. We further show that censoring has different effects on the estimation of the measure for the Cox model than for parametric models, and we discuss them separately. We also give some warnings about the usage of the measure, especially when it comes to comparing essentially different models.     

Selection and implementation of a PPC system

There are many computer-aided production planning and control (PPC) systems available on the market which can provide a solution to the complex task of production planning and control. However, the question remains, how can a company find an optimal system from the vast amount of available systems? This article proposes that a company, having decided to buy one of the available systems, starts a project for selection and implementation of the PPC system.     

Policy measures in the deleveraging process: A macroprudential evaluation

This paper evaluates post-crisis effects of deleveraging policy in Slovenia. Reductions in banks’ credits to nonfinancial sectors were driven by increased collateralization, credit rationing, and a neglect of cash flow performance of banking clients. These jeopardized the normal deleveraging of companies with positive cash flows, and rolling over credits, which stifled economic growth. Erroneous sequencing, timing, and calibration of measures steering the deleveraging process generated these processes. Optimal deleveraging process demands that the Central Bank also focus on the stability of the financial system. This task should be a constitutional part of the third macro policy pillar, namely macroprudential policy.     

Canopy precipitation interception in urban forests in relation to stand structure

Urban forests provide important ecosystem services. In terms of hydrological benefits, forest ecosystems in urban environments represent qualitative and quantitative filter for rainwater. We quantified the canopy interception in relation to urban forest stand structure and rainfall intensity in an urban transect of the mixed (upland) forest in the city centre, towards a riparian pine forest and a floodplain hardwood forest in the City of Ljubljana, Slovenia. Bulk precipitation in open areas and throughfall were measured with fixed rainfall collectors in each forest. Stemflow was estimated from a review of relevant literature. We found that canopy interception in selected urban forests was mainly affected by tree species composition and other stand structure variables, such as canopy cover and tree dimensions. Average annual canopy interception was highest in the mixed forest (18.0% of bulk precipitation), while the riparian pine forest had the lowest level (3.9% of bulk precipitation) and the floodplain hardwood forest had the intermediate level for interception (7.1% of bulk precipitation). The mixed forest exhibited the stand structure factors that contributed to the highest canopy interception among the studied forests: high assemblage of dominant coniferous trees, denser canopy cover and the highest growing stock. Furthermore, rainfall intensity has proven to be an important factor for the seasonal partitioning (comparing the leafed and leafless period) of canopy interception. A better understanding of precipitation interception processes in urban forests is needed to assist urban forest managing and planning, aiming at maximizing canopy interception for the mitigation of stormwater runoff and flooding in urbanized watershed.