The rate and potential of capability development trajectories

This paper examines differences in the rate and potential of firms' capability development trajectories. Capability development trajectories are the paths over which firms' capabilities change with experience and other activities. While prior research focused on factors affecting capability development rate (the fraction of the gap between a firm's current and potential capability eliminated with each unit of activity), we argue that capability development trajectories also differ in potential (the maximum capability level a firm could achieve through repeating a given set of activities over time). We develop and estimate a formal model of capability development, showing that larger underwriting projects lead to a lower rate of improvement toward higher potential capabilities, and derive implications for research on industry dynamics and the nature of competitive advantage. Copyright © 2013 John Wiley & Sons, Ltd.     

Rational functions: an alternative approach to asset pricing

This paper shows that asset prices are linear polynomials of various underlying explanatory factors and asset returns being ratios of these polynomials, are rational functions that do not add linearly when averaging. Hence, average returns should be modeled based on stock prices. However, continuous returns may be treated as approximately linear across time and modeled directly. Our new Rational Function (RF) models, empirically outperform the traditional asset pricing models like the Capital Asset Pricing Model (CAPM) and the Fama–French three and five-factor models for both average and continuous returns. Moreover, the RF theory also provides a model to estimate the asset volumes. The average change in asset volumes together with average returns provide the estimates for average change in market values of assets. Thus, the RF model approach can be used to select assets that provide either highest returns for profit maximization or highest change in market values for wealth maximization for given levels of risk.     

A semiparametric analysis of calorie response to income change across income groups and gender

This paper estimates the relationship between calorie intake and income within a semiparametric framework, which allows for heterogeneity across individuals and possible nonlinearity in the relationship. The results, using a panel data set from rural south India, indicate that the income elasticity of calorie intake is small but is nonzero and statistically significant, and that the elasticity is higher for the relatively poor households in the sample. The semiparametric analysis also brings out some interesting patterns of calorie response to income change at different income levels for males and females.     

On statistical inference for inequality measures calculated from complex survey data

We examine inference for Generalized Entropy and Atkinson inequality measures with complex survey data, using Wald statistics with variance?Ccovariance matrices estimated from a linearization approximation method. Testing the equality of two or more inequality measures, including sub-group decomposition indices and group shares, are covered. We illustrate with Indian data from three surveys, examining pre-school children??s height, an anthropometric measure that can indicate long-term malnutrition. Sampling involved an urban/rural stratification with clustering before selection of households. We compare the linearization complex survey outcomes with those from an incorrect independently and identically distributed (iid) assumption and a bootstrap that accounts for the survey design. For our samples, the results from the easy to implement linearization method and the more computationally burdensome bootstrap are typically quite similar. This finding is of interest to applied researchers, as bootstrapping is currently the method that is most commonly used for undertaking statistical inference in this literature.     

The association of pain interference and opioid use with healthcare utilization and costs,and wage loss among adults with osteoarthritis in the United States

Abstract

Aim: To examine associations of opioid use and pain interference with activities (PIA), healthcare resource utilization (HRU) and costs, and wage loss in noninstitutionalized adults with osteoarthritis in the United States (US).

Methods: Adults with osteoarthritis identified from the Medical Expenditure Panel Survey for 2011/2013/2015 were stratified by no-opioid use with no/mild PIA, no-opioid use with moderate/severe PIA, opioid use with no/mild PIA, and opioid use with moderate/severe PIA. Outcomes included annualized total HRU, direct healthcare costs, and wage loss. Multivariable regression analyses were used for comparisons versus no-opioid use with no/mild PIA (referent). The counterfactual recycled prediction method estimated incremental costs. Results reflect weighted nationally representative data.

Results: Of 4,921 participants (weighted n?=?20,785,007), 46.5% had no-opioid use with no/mild PIA; 23.2% had no-opioid use with moderate/severe PIA; 9.6% had opioid use with no/mild PIA; and 20.7% had opioid use with moderate/severe PIA. Moderate/severe PIA and/or opioid use were associated with significantly higher HRU and associated costs, and wage loss. Relative to adults with no/mild PIA, opioid users with moderate/severe PIA were more likely to have hospitalizations, specialist visits, and emergency room visits (all p?<?.001). Relative to the referent, opioid use with no/mild PIA had higher per-patient incremental annual total healthcare costs ($11,672, 95% confidence interval [CI]?=?$11,435–$11,909) and wage loss ($1,395, 95% CI?=?$1,376–$1,414) as did opioid use with moderate/severe PIA ($13,595, 95% CI?=?$13,319–$13,871; and $2,331, 95% CI?=?$2,298–$2,363) (all p?<?.001). Compared with the referent, estimated excess national total healthcare costs/lost wages were $23.3 billion/$1.3 billion for opioid use with no/mild PIA, and $58.5 billion/$2.2 billion for opioid use with moderate/severe PIA.

Limitations: Unobservable/unmeasured factors that could not be accounted for.

Conclusions: Opioid use with moderate/severe PIA had significantly higher HRU, costs, and wage loss; opioid use was more relevant than PIA to the economic burden. These results suggest unmet needs for alternative pain management strategies.