Using firm data to assess the performance of equilibrium search models of the labor market

Equilibrium search models are useful tools for the evaluation of labor market policies. Recently developed equilibrium search models of the labor market are able to fit the wage distribution perfectly with longitudinal labor supply data, by estimating an appropriate distribution of labor productivity across firms. This paper formally compares such structural estimates to their directly observed counterparts in firm data. More generally, we investigate the extent to which these models are able to explain the observed distributions of wages, productivities and firm sizes across firms, as well as the extent to which they are able to explain the observed relationships between these variables across firms. The parameters that capture search frictions are estimated with worker data that are matched to the data

Opportunities to optimise colistin stewardship in hospitalised patients in South Africa: Results of a multisite utilisation audit

Background. Colistin is an old antibiotic that has been reintroduced as salvage therapy in hospitalised patients because it is frequently the only agent active against Gram-negative bacteria. Various guidelines for colistin administration have led to confusion in establishing the appropriate dose, which has potential for adverse consequences including treatment failure or toxicity. The emergence and spread of colistin resistance has been documented in South Africa (SA), but no local information exists on how and why colistin is used in  hospitals, and similarly, compliance with current dosing guidelines is unknown.Objectives. To evaluate the current utilisation of colistin in SA hospitals, in order to identify stewardship opportunities that could enhance the appropriate use of this antibiotic.Methods. Electronic patient records of adult patients on intravenous (IV) colistin therapy for >72 hours in four private hospitals were retrospectively audited over a 10-month period (1 September 2015 - 30 June 2016). The following data were recorded: patient demographics, culture and susceptibility profiles, diagnosis, and indication for use. Compliance with six colistin process measures was audited: obtaining a culture prior to initiation, administration of a loading dose, administration of the correct loading dose, adjustments to maintenance dose according to renal function, whether colistin was administered in combination with another antibiotic, and whether de-escalation following culture and sensitivity results  occurred. Outcome measures included effects on renal function, overall hospital mortality, intensive care unit length of stay (LoS), and hospital LoS.Results. Records of 199 patients on IV colistin were reviewed. There was 99.0% compliance with obtaining a culture prior to antibiotic therapy, 93.5% compliance with prescription of a loading dose, and 98.5% compliance regarding prescription of colistin in combination with another agent. However, overall composite compliance with the six colistin stewardship process measures was 82.0%. Non-compliance related to inappropriate loading and  maintenance doses, lack of adjustment according to renal function and lack of de-escalation following culture sensitivity was evident. Significantly shorter durations of treatment were noted in patients who received higher loading doses (p=0.040) and in those who received maintenance doses of 4.5 MU twice daily v. 3 MU three times daily (p=0.0027). In addition, compared with patients who survived, more patients who died received the 3 MU three times daily maintenance dose (p=0.0037; phi coefficient 0.26).Conclusions. The study identified multiple stewardship opportunities to optimise colistin therapy in hospitalised patients. Urgent implementation of a stewardship bundle to improve colistin utilisation is warranted.

Returns to Tenure or Seniority?

This study documents two empirical regularities, using data for Denmark and Portugal. First, workers who are hired last, are the first to leave the firm (Last In, First Out; LIFO). Second, workers’ wages rise with seniority (= a worker’s tenure relative to the tenure of her colleagues). We seek to explain these regularities by developing a dynamic model of the firm with stochastic product demand and hiring cost (= irreversible specific investments). There is wage bargaining between a worker and its firm. Separations (quits or layoffs) obey the LIFO rule and bargaining is efficient (a zero surplus at the moment of separation). The LIFO rule provides a stronger bargaining position for senior workers, leading to a return to seniority in wages. Efficiency in hiring requires the workers’ bargaining power to be in line with their share in the cost of specific i