Firm dynamics, markup variations, and the business cycle

We present a model in which net business formation is endogenously procyclical. Variations in the number of operating firms lead to countercyclical variations in markups that give rise to endogenous procyclical movements in measured total factor productivity (TFP). Based on this result, the paper suggests a simple structural decomposition of variations in TFP into those originating from exogenous shocks and those originating endogenously from the interaction between firms’ entry and exit decisions and the degree of competition. The decomposition suggests that around 40% of the movements in measured TFP can be attributed to this interaction. Moreover, the paper analyzes the effects on (i) the measurement of the volatility of exogenous shocks in the U.S. economy and (ii) the magnification of shocks over the business cycle.     

Phase transition in the S&P stock market

We analyze the returns of stocks contained in the Standard & Poor’s 500 index from 1987 until 2011. We use covariance matrices of the firms’ returns determined in a time windows of several years. We find that the eigenvector belonging to the leading eigenvalue (the market) exhibits a phase transition. The market is in an ordered state from 1995 to 2005 and in a disordered state after 2005. We can relate this transition to an order parameter derived from the stocks’ beta and the trading volume. This order parameter can also be interpreted within an agent-based model.     

Rentenreform — mit welchem Fokus?

The demographic imbalance is aggravating, and by 2060 the old-age dependency ratio will double to approximately 70%. This development has consequences for the state pension system: growing contribution rates to social security coupled with lower pension levels, but at the same time a higher retirement age. The German pension scheme is mandatory for all wage and salary earners, but since 2001, no reasonable indicator for measuring the pension level exists any more. As a consequence of this, old-age pension has lost its traditional function as a replacement for earnings. The recent pension reforms have dropped the pension level sharply. Further reductions have been announced with the consequence of increasing old age poverty. Against this background it is proposed to raise the pension level so that the pensioners can maintain their standard of living. But any pension reform involves issues of distribution between and often also within generations, which cannot be addressed without explicit equity criteria. Some authors consider the past reforms as a mistake, others suggest adjustments.     

Der US-Dollar als Leitwährung – alternativlos?

The importance of the industrialized countries – including the USA – for world production has been declining for a long time. By contrast, China’s share in particular has increased significantly. Nevertheless, the US dollar has largely fulfilled the criteria for a leading currency function so far, even if this is increasingly criticised due to the protectionist rhetoric of the US. Accordingly, central banks worldwide hold their reserves primarily in US dollars and transactions are largely conducted in US currency. This position brings great advantages–such as making it easier for the US to monitor and enforce sanctions, among other things–and therefore great incentives for the US to maintain its position as the leading currency. Whether other currencies, especially the renminbi, will be able to fulfil the lead currency function is questionable. Similarly, it does not seem realistic that market participants will be able to engage in a global currency.     

Clinical and economic benefits of professional CGM among people with type 2 diabetes in the United States: analysis of claims and lab data

Background: It is estimated that one in 10 people in the US have a diagnosis of diabetes. Type 2 diabetes accounts for 95% of all cases in the US, with annual costs estimated to be $246 billion per year. This study investigated the impact of a glucose-measuring intervention to the burden of type 2 diabetes.

Objective: This analysis seeks to understand how professional continuous glucose monitoring (professional CGM) impacts clinical and economic outcomes when compared to patients who are not prescribed professional CGM.

Methods: This study utilized a large healthcare claims and lab dataset from the US, and identified a cohort of patients who were prescribed professional CGM as identified by CPT codes 95250 and 95251. It calculated economic and clinical outcomes 1 year before and 1 year after the use of professional CGM, using a generalized linear model.

Results: Patients who utilized professional CGM saw an improvement in hemoglobin A1C. The “difference-in-difference” calculation for A1C was shown to be –0.44%. There was no statistically significant difference in growth of total annual costs for people who used professional CGM compared to those who did not ($1,270, p?=?.08). Patients using professional CGM more than once per year had a –$3,376 difference in the growth of total costs (p?=?.05). Patients who used professional CGM while changing their diabetes treatment regimen also had a difference of –$3,327 in growth of total costs (p?=?.0023).

Conclusion: Significant clinical benefits were observed for patients who used professional CGM. Economic benefits were observed for patients who utilized professional CGM more than once within a 1-year period or who used it during a change of diabetes therapy. This suggests that professional CGM may help decrease rising trends in healthcare costs for people with type 2 diabetes, while also improving clinical outcomes.     

Association between provider specialty and healthcare costs and glycemic control for patients with diabetes

Aims: To analyze the association between provider, healthcare costs, and glycemic control for patients with diabetes mellitus (DM).

Materials and methods: This cross-sectional study identified adults with type 1 or 2?DM (T1D, T2D) in the Optum database. The main independent variable was provider (endocrinologist or primary care). Regression analysis compared total medical and pharmacy costs, adjusting for health status and other patient differences, by provider.

Results: For all patients, HbA1C improvement was greater, and medical costs significantly lower with an endocrinologist rather than a primary care provider. The largest HbA1C improvement (4%) occurred for insulin-dependent patients seen by endocrinologists. Significant medical savings with endocrinologist management occurred within the Medicare Advantage population in every sub-group of patients, with 14% lower costs ($4,767) for patients with T1D, 11% lower costs ($3,160) for patients with macro- and microvascular complications, and 10% lower costs ($2,237) for insulin-dependent patients. Within the commercial insurance population, medical costs were reduced by ≥9% in every sub-group of patients, with a 20% reduction ($8,450) for patients with micro- and macrovascular complications. Overall total costs (medical and pharmacy) were 8% ($1,541) higher for patients receiving endocrinologist rather than primary care, although endocrinologist care resulted in a 9% reduction (–$3,710) in costs for Medicare Advantage patients with T1D. Total medical costs (excluding pharmacy costs) may be a more accurate indicator of costs associated with patients in various stages of DM.

Limitations: There was insufficient data to develop risk-adjustment payments for pharmacy costs based on disease severity. The cross-sectional design identifies associations and not cause–effect relationships.

Conclusion: DM management by an endocrinologist was associated with greater HbA1C improvement and significantly lower medical costs. Total costs were higher with an endocrinologist, but for patients with T1D lower costs were seen, ranging from 2–9% regardless of insurance type.     

Real option pricing with mean-reverting investment and project value

In this work, we are concerned with valuing the option to invest in a project when the project value and the investment cost are both mean-reverting. Previous works on stochastic project and investment cost concentrate on geometric Brownian motions (GBMs) for driving the factors. However, when the project involved is linked to commodities, mean-reverting assumptions are more meaningful. Here, we introduce a model and prove that the optimal exercise strategy is not a function of the ratio of the project value to the investment V/I – contrary to the GBM case. We also demonstrate that the limiting trigger curve as maturity approaches traces out a nonlinear curve in (V, I) space and derive its explicit form. Finally, we numerically investigate the finite-horizon problem, using the Fourier space time-stepping algorithm of Jaimungal and Surkov [2009. Lev´y based cross-commodity models and derivative valuation. SIAM Journal of Financial Mathematics, to appear. http://www.ssrn.com/abstract=972837]. Numerically, the optimal exercise policies are found to be approximately linear in V/I; however, contrary to the GBM case they are not described by a curve of the form V*/I*=c(t). The option price behavior as well as the trigger curve behavior nicely generalize earlier one-factor model results.     

Dis-Ag-reement: the construction and negotiation of risk in the Swedish controversy over antibacterial silver

What constitutes a potentially hazardous object is often debated. This article analyses the polemic construction and negotiation of risk in the Swedish controversy over the use of antibacterial silver in health care and consumer products. This debate engages the media, government agencies, parliament and government, non-governmental organizations and companies. Texts and websites from these actors were studied using content analysis. Antibacterial silver is construed by some actors as a risk object with harmful effects on a series of objects at risk: the environment, public health, organisms and sewage treatment. In contrast, other actors deny that antibacterial silver is a risk object, instead construing it as mitigating risk. In such a schema, antibacterial silver is conceived of as managing the risk objects of bacteria and micro-organisms, in turn managing the risk objects of infection, bad smell and washing, and in turn helping the environment and public health (objects at risk). The structure of the debate suggests two basic modes of risk communication. First, antibacterial silver is construed as a risk object, endangering a variety of objects at risk, such as organisms, public health, the environment and sewage treatment. Second, this association between antibacterial silver and objects at risk is obstructed, by denying that antibacterial silver is a risk object or by associating silver with the benefit of mitigating risk.     

Optimal Harvesting of an Age-Structured Schooling Fishery

Biologists have criticized traditional biomass models in fishery economics for being oversimplified. Biological stock assessment models are more sophisticated with regard to biological content, but rarely account for economic objectives. This study includes a full age-structured population model for studying schooling fisheries and extends the delayed difference approach used in earlier studies. We take the total harvest as the choice variable, resulting in a simple analytical structure. The model produces optimal steady states that may be higher or lower compared to the delayed-difference formulation. The model is applied to the Baltic sprat fishery. Both ecological and harvesting cost data support specifying Baltic sprat as a schooling fishery. Given nonlinear harvesting costs, the optimal solution is a path toward a steady state with smooth annual harvest and population age structure. Sensitivity analysis shows that the optimal solution is highly dependent on the population level of the sprat’s main predator Baltic cod. A linear cost function and an interest rate below 9 % imply pulse fishing instead of smooth continuous harvesting. Given nonlinear harvesting cost, the optimal steady state yield is rather insensitive to changes in the interest rate. However, under a high cod scenario, interest rates of 10 % or higher implies that no optimal steady state exists.