Unexplained Differences Research Articles

The risk in using financial reports in the study of airline business models

A review of published articles has shown that many researchers use financial reports as the main source of information in regard to airline business models. A study of accounting policies and other external information, however, has highlighted the differences in assumptions as to useful lives and the residual values of aircraft, which are the principal assets of airlines. While the considerable, unexplained differences in the accounting policies of enterprises with similar business models indicate there may be risk in using this data, the risk can be eliminated by making appropriate adjustments in the financial statements.

Individual and Clustered Rankability of ICUs According to Case-Mix–Adjusted Mortality*

The performance of ICUs can be compared by ranking them into a league table according to their risk-adjusted mortality rate. The statistical quality of a league table can be expressed as its rankability, the percentage of variation between ICUs attributable to unexplained differences. We examine whether we can improve the rankability of our league table by using data from a longer period or by grouping ICUs with similar performance constructing a league table of clusters rather than individual ICUs. We developed a league table for risk-adjusted mortality rate with its rankability. The effect of assessment period was determined using a resampling procedure. Hierarchical clustering was used to obtain clusters of similar ICUs. We used data from ICUs participating in the Dutch National Intensive Care Evaluation registry between 2011 and 2013. We constructed league tables using 157,394 admissions from 78 ICUs with risk-adjusted mortality rate between 5.9% and 13.9% per ICU over the inclusion period. The rankability was 73% for 2013 and 89% for the whole period 2011-2013. Rankability over the year 2013 increased till 98% when clustering ICUs, reaching an optimum at a league table of seven clusters. We conclude that, when using data from a single year, the rankability of a league table of Dutch ICUs based on risk-adjusted mortality rate was unacceptably low. We could improve the rankability of this league table by increasing the period of data collection or by grouping similar ICUs into clusters and constructing a league table of clusters of ICUs rather than individual ICUs. Ranking clusters of ICUs could be useful for identifying possible differences in performance between clusters of ICUs.

Race and Gender Differences in the Use of Direct Acting Antiviral Agents for Hepatitis C Virus.

Direct acting antiviral agents (DAA) are highly effective yet expensive. Disparities by race and/or gender often exist in the use of costly medical advances as they become available. We examined a cohort of hepatitis C virus (HCV) patients who received care at the Veterans Administration facilities nationwide. We evaluated the effect of race and gender on DAA receipt after adjusting for socioeconomic status, liver disease severity, comorbidity, and propensity for healthcare use. To determine if disparities had changed over time, we conducted a similar analysis of HCV patients who were seen in the previous standard of care treatment era. Of the 145 596 patients seen in the current DAA era, 17 791 (10.2%) received treatment during the first 16 months of DAA approval. Black patients had 21% lower odds of receiving DAA than whites (odds ratio [OR] = 0.79; 95% confidence interval [CI], .75, .84). Overall, women were as likely to receive treatment as men (OR = 0.99; 95% CI, .90-1.09). However, the odds of receiving DAAs were 29% lower for younger women compared with younger men (OR = 0.71, 95% CI, .54-.93). Similar to the DAA cohort, black patients had significantly lower odds of receiving treatment than whites (OR = 0.74, 95% CI, .69-.79) in the previous treatment era. The racial difference between the 2 eras did not reach statistical significance. There were unexplained differences among HCV population subgroups in the receipt of new DAA treatment. Targeted interventions are needed for black patients and younger women.

Understanding recent internal migration of small cultural groups in England and Wales

ABSTRACTTaking advantage of the availability of 2011 England and Wales census microdata, and recognising the importance of internal migration in shaping the size and nature of communities, this paper seeks to identify and quantify the underlying determinants of internal migration of small cultural groups. The Jewish group is one of the longest present minority groups in Britain. Three other groups (Arab, Chinese, and Sikh), which have been present in significant numbers for a much shorter period, are also examined. Multivariate binary logistic regression has been applied to data extracted from the 2011 safeguarded microdata files, to understand whether, having controlled for the variables identified, there remain residual unexplained differences between Jewish, other smaller group, and general migration levels. The study shows that the initial wide variation in migration propensity between these cultural groups is partly explained by compositional differences between groups, but that even after controlling for individual-level socio-demographic characteristics, regional location and distance of migration, cultural differences in migration behaviour remain. Overall, the study shows that there are fewer differences between Jewish and white British migration levels than for the other three groups, for whom a small but significant ‘cultural group penalty’, inhibiting migration propensity, remains.

Racial/Ethnic Pay Disparities among Registered Nurses (RNs) in U.S. Hospitals: An Econometric Regression Decomposition.

To detect the presence of racial and ethnic pay disparities between minority and white hospital RNs using a national sample. The National Sample Survey of Registered Nurses, 2008, which is representative at both the state and national level. Cross-sectional data were analyzed using multivariate regression and regression decomposition. Differences between groups were decomposed into differences in the possession of characteristics and differences in the value of the same characteristic between different groups, the latter being a commonly used measure of wage discrimination. As the majority of minority hospital RNs are employed within the most densely populated (central) counties of metropolitan statistical areas (MSAs), only hospital RNs employed in the central counties of MSAs were selected. Regression decomposition found that black and Hispanic RNs earned less than whites and Asians, while Asian RNs earned more than white RNs. The majority of pay variation between white RNs, versus Asian, black, or Hispanic RNs was due to unexplained differences in the value of the same characteristic between groups. Differences in earnings between underrepresented and overrepresented hospital RNs is suggestive of discrimination.

Simulating the escaping atmospheres of hot gas planets in the solar neighborhood

Absorption of high-energy radiation in planetary thermospheres is believed to lead to the formation of planetary winds. The resulting mass-loss rates can affect the evolution, particularly of small gas planets. We present 1D, spherically symmetric hydrodynamic simulations of the escaping atmospheres of 18 hot gas planets in the solar neighborhood. Our sample only includes strongly irradiated planets, whose expanded atmospheres may be detectable via transit spectroscopy. The simulations were performed with the PLUTO-CLOUDY interface, which couples a detailed photoionization and plasma simulation code with a general MHD code. We study the thermospheric escape and derive improved estimates for the planetary mass-loss rates. Our simulations reproduce the temperature-pressure profile measured via sodium D absorption in HD 189733 b, but show unexplained differences in the case of HD 209458 b. In contrast to general assumptions, we find that the gravitationally more tightly bound thermospheres of massive and compact planets, such as HAT-P-2 b are hydrodynamically stable. Compact planets dispose of the radiative energy input through hydrogen Ly$\alpha$ and free-free emission. Radiative cooling is also important in HD 189733 b, but it decreases toward smaller planets like GJ 436 b. The simulations show that the strong and cool winds of smaller planets mainly cause strong Ly$\alpha$ absorption but little emission. Compact and massive planets with hot, stable thermospheres cause small absorption signals but are strong Ly$\alpha$ emitters, possibly detectable with the current instrumentation. The absorption and emission signals provide a possible distinction between these two classes of thermospheres in hot gas planets. According to our results, WASP-80 and GJ 3470 are currently the most promising targets for observational follow-up aimed at detecting atmospheric Ly$\alpha$ absorption signals.

Disordered Regions Flanking Ordered Domains Modulate Signaling Transduction

Signals generated by cell surface receptors are transduced and relayed to downstream intracellular signaling pathways typically through proteins in which folded domains are flanked by regions that are unstructured or only partially structured. Such signaling systems are often multidomain proteins in which disordered linkers provide an effective means to covalently tether and colocalize globular modules (1). However, in several regulatory proteins, linkers have been reported to serve not only as passive covalent tethers, but also as active modulators of the function elicited by adjacent domains (2–4).

Abstract 17129: Differences in Work Activities and Compensation of Male and Female Cardiologists in Community Practice in 2013

Background: Despite laudable efforts to increase gender diversity in cardiology, much remains unknown about the experiences - including working activities and pay - of those women who have joined this still predominantly male specialty. Hypothesis: We hypothesized that a gender difference in compensation would exist on unadjusted analyses and that this could be explained by differences in the many personal, job, and practice characteristics measured in our dataset. Methods: Using the 2013 annual practice survey of MedAxiom, a subscription-based service provider for cardiology practices, we described personal, job, and practice characteristics of cardiologists from 161 practices and their salary by gender. Multivariable linear regression analysis and the Peters-Belson technique of labor economics were applied to evaluate gender differences. Results: Of 2679 subjects, 229 (8.5%) were female and 2450 male. Women were more likely to have specialized in general/non-invasive cardiology (53.1% vs 28.2%), and a lower proportion (11.4% vs 39.3%) reported an interventional subspecialty compared to men. Numerous job characteristics differed by gender, including the proportion working full-time (79.9% of women vs 90.9% of men, p<0.001), number of half-days worked (median 422 for women vs 433 for men, p=0.001), and wRVUs generated (median 7430 for women vs 9301 for men, p<0.001). Median salary was $394,586 (IQR: $256,064; $518,277) among women and $502,251 ($381,417; $621,306) among men. Peters-Belson analysis revealed that the women in this sample would have been expected to have a mean salary of $432,631, based on their productivity and other characteristics, had they been male, but the actual observed mean salary among women was $400,882 (unexplained difference=$31,749, 95% CI $16,303 - $48,028). Multivariable linear regression analysis yielded significant results similar in direction and magnitude. Conclusions: This study provides novel information about the diverse jobs held by men and women practicing cardiology in the US today. The observed gender difference in compensation, which remained substantial and significant even after adjusting for differences in multiple measures of productivity and job activity, merits attention.

How much of the difference in life expectancy between Scottish cities does deprivation explain?

BackgroundGlasgow’s low life expectancy and high levels of deprivation are well documented. Studies comparing Glasgow to similarly deprived cities in England suggest an excess of deaths in Glasgow that cannot be accounted for by deprivation. Within Scotland comparisons are more equivocal suggesting deprivation could explain Glasgow’s excess mortality. Few studies have used life expectancy, an intuitive measure that quantifies the between-city difference in years. This study aimed to use the most up-to-date data to compare Glasgow to other Scottish cities and to (i) evaluate whether deprivation could account for lower life expectancy in Glasgow and (ii) explore whether the age distribution of mortality in Glasgow could explain its lower life expectancy.MethodsSex specific life expectancy was calculated for 2007–2011 for the population in Glasgow and the combined population of Aberdeen, Dundee and Edinburgh. Life expectancy was calculated for deciles of income deprivation, based on the national ranking of datazones, using the Scottish Index of Multiple Deprivation. Life expectancy in Glasgow overall, and by deprivation decile, was compared to that in Aberdeen, Dundee and Edinburgh combined, and the life expectancy difference decomposed by age using Arriaga’s discrete method.ResultsLife expectancy for the whole Glasgow population was lower than the population of Aberdeen, Dundee and Edinburgh combined. When life expectancy was compared by national income deprivation decile, Glasgow’s life expectancy was not systematically lower, and deprivation accounted for over 90 % of the difference. This was reduced to 70 % of the difference when carrying out sensitivity analysis using city-specific income deprivation deciles. In both analyses life expectancy was not systematically lower in Glasgow when stratified by deprivation. Decomposing the differences in life expectancy also showed that the age distribution of mortality was not systematically different in Glasgow after accounting for deprivation.ConclusionsLife expectancy is not systematically lower across the Glasgow population compared to Aberdeen, Dundee and Edinburgh combined, once deprivation is accounted for. This provides further evidence that tackling deprivation in Glasgow would probably reduce the health inequalities that exist between Scottish cities. The change in the amount of unexplained difference when carrying out sensitivity analysis demonstrates the difficulties in comparing socioeconomic deprivation between populations, even within the same country and when applying an established ecological measure. Although the majority of health inequality between Glasgow and other Scottish cities is explained by deprivation, the difference in the amount of unexplained inequality depending on the relative context of deprivation used demonstrates the challenges associated with attributing mortality inequalities to an independent ‘place effect’.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-2358-1) contains supplementary material, which is available to authorized users.

Decomposition and wage inequality

Earning differentials are investigated by a quantile regressions based decomposition, which disentangles the inequalities linked to the covariates and coefficients at various quantiles. Gender and region are considered the main sources of inequality. The unexplained gender and regional differences decrease at the highest wages. Their combination at the lower wages’ level affects women more, causing a so-called sticky floor. Gender and regional covariate effects show a prevalence of women covariates compared with the men’s group, and a prevalence of southern women covariates within the women’s group, particularly at the higher quantiles. This can be interpreted as a glass ceiling hindering southern women at higher wages.

Does assimilation work? Sociocultural determinants of labour market participation of European Muslims

ABSTRACTNumerous studies have shown that even after controlling for relevant socio-economic background variables, the labour market position of immigrant minorities lags considerably behind that of natives. The label ‘ethnic penalties’ is often used to denote these gaps and reflects the idea that differences between natives and immigrants that cannot be explained by demographic and human capital variables must be due to discrimination by employers. I challenge this interpretation by looking at the role of sociocultural variables such as language proficiency, interethnic social ties and gender values as alternative sources of unexplained ethnic group differences. I use the data from the cross-national ‘Eurislam’ survey of four immigrant ethnic groups of predominantly Muslim belief—Turks, Moroccans, former Yugoslav Muslims and Pakistani—as well as native ethnics. The results indicate that once sociocultural variables are taken into account, differences in rates of labour market participation and unemployment between native ethnics and the Muslim groups are strongly reduced and in many cases become statistically insignificant. Using mediation analyses, I demonstrate that the findings do not fit a scenario that assumes that the causality primarily flows from labour market participation to sociocultural assimilation rather than the other way around.

Aspirin response: Differences in serum thromboxane B2 levels between clinical studies

Serum thromboxane B2 (TxB2) is a specific marker of platelet inhibition by aspirin. Yet, TxB2 levels differ by up to 10-fold between some aspirin-treated patient cohorts. This study aimed to identify factors responsible for differences in serum TxB2 between cohorts in the ADRIE study (n = 657) and the BOSTON study (n = 678) of aspirin-treated cardiovascular patients originally tested with different ELISA assays. TxB2 levels were assessed in representative subgroups of the two cohorts (34 samples in BOSTON and 39 in ADRIE) by both ELISAs, as well as liquid chromatography and tandem mass spectroscopy (MS). A multivariate analysis was performed on the whole cohort database to identify determinants of the difference of TxB2 levels between cohorts. There was no systematic bias between the original ELISA TxB2 values and the MS values and the median difference was small, 0.12 ng/ml, thus not explaining the difference between median TxB2 levels in the two study populations (7 and 0.6 ng/ml in the ADRIE and BOSTON studies, respectively). In the combined dataset of the ADRIE and BOSTON cohorts (n = 1342), body mass index, age, gender, aspirin dose, time from aspirin intake to blood draw, NSAID intake, platelet count and C-reactive protein were significantly associated with TxB2 levels. After adjustment for patient characteristics, the difference between cohorts did not decrease. Unexplained differences in serum TxB2 levels in different populations of aspirin-treated cardiovascular patients suggest that further studies are needed to confirm the role of serum TxB2 level as a prognostic factor or rather as a marker of therapeutic observance.

The effect of frictional pressure, geometry and wall friction on the modelling of a pseudo-2D bubbling fluidised bed reactor

The two fluid model (TFM) closed by the kinetic theory of granular flows (KTGF) has been developed to a high level of maturity over the past three decades. However, significant uncertainties still remain about the influence of various closure models on the predictions of the hydrodynamics and especially the reactive performance of fluidised bed reactors. The three factors investigated in this study – frictional pressure, geometry (2D/3D) and friction at the walls – all have significant influences on model predictions of the behaviour of a pseudo-2D bubbling fluidised bed reactor. This study aims to quantify the influence of these important factors on simulation output both in terms of hydrodynamics and reactive performance. Simulations designed to evaluate the effects of these factors were carried out over a wide range of fluidisation velocities, bed loadings and particle sizes to reveal significant impacts on the results. Differences in simulation results varied significantly with changes in the three operating variables investigated (fluidisation velocity, bed loading and particle size) and were analysed in detail. Finally, 3D simulations with wall friction and frictional pressure included showed qualitatively very similar hydrodynamic behaviour to that observed in the experiments. Quantitatively, measurements of the bed expansion ratio compared well for different fluidisation velocities and the particle sizes, but some unexplained differences were still observed in response to changes in the bed loading.

Emergency department management of syncope: need for standardization and improved risk stratification.

Variations in emergency department (ED) syncope management have not been well studied. The goals of this study were to assess variations in management, and emergency physicians' risk perception and disposition decision making. We conducted a prospective study of adults with syncope in six EDs in four cities over 32 months. We collected patient characteristics, ED management, disposition, physicians' prediction probabilities at index presentation and followed patients for 30 days for serious outcomes: death, myocardial infarction (MI), arrhythmia, structural heart disease, pulmonary embolism, significant hemorrhage, or procedural interventions. We used descriptive statistics, ROC curves, and regression analyses. We enrolled 3662 patients: mean age 54.3 years, and 12.9 % were hospitalized. Follow-up data were available for 3365 patients (91.9 %) and 345 patients (10.3 %) suffered serious outcomes: 120 (3.6 %) after ED disposition including 48 patients outside the hospital. After accounting for differences in patient case mix, the rates of ED investigations and disposition were significantly different (p < 0.0001) across the four study cities; as were the rates of 30-day serious outcomes (p < 0.0001) and serious outcomes after ED disposition (p = 0.0227). There was poor agreement between physician risk perception and both observed event rates and referral patterns (p < 0.0001). Only 76.7 % (95 % CI 68.1-83.6) of patients with serious outcomes were appropriately referred. There are large and unexplained differences in ED syncope management. Moreover, there is poor agreement between physician risk perception, disposition decision making, and serious outcomes after ED disposition. A valid risk-stratification tool might help standardize ED management and improve disposition decision making.

Variation in Juvenile Steelhead Density in Relation to Instream Habitat and Watershed Characteristics

AbstractPhysical habitat characteristics can affect the abundance and distribution of organisms, and are frequently used to predict the standing crop of stream fish for purposes of understanding their ecology and better direct management. However, the spatial scale of the investigation and the resolution of the data can affect the outcome of such analyses. In this study we coupled watershed‐level characteristics with instream habitat variables to model the density of two age‐classes of juvenile steelhead Oncorhynchus mykiss in a watershed in the Clearwater River basin, Idaho. Density varied considerably across time and space. Variance partitioning showed that 41–50% of the variances in density were due to unexplained differences between sampling occasions (residual variance), and the rest resulted from variation at the site and site‐and‐year levels, depending on the age‐class. Instream habitat variables better explained the variation in density than did models that included watershed‐level characteristics. The density of subyearling steelhead was best explained by stream discharge, with a negative relationship. The density of yearling steelhead was best explained by a negative relationship with average weekly temperature; however, this relationship was statistically indistinguishable from zero. Finally, total density (subyearlings and yearlings combined) was best explained by discharge and average daily temperature. We believe that our approach is useful for identifying the physical factors associated with the density of stream salmonids, but we stress that findings from correlative studies should be interpreted in concert with detailed knowledge about life history variation in the study system.

Ethnic differences in children's socioemotional difficulties: Findings from the Millennium Cohort Study

This paper investigates ethnic differences in children's socioemotional difficulties and possible explanations for any observed inequalities. We used data collected from the fourth sweep of the Millennium Cohort Study when children were aged 7 years. We found that Pakistani, Bangladeshi, and Black Caribbean children had significantly more socioemotional difficulties than White children. These differences were partially explained by the relative socioeconomic disadvantage of their families. After accounting for maternal and family environment factors, the differences for Pakistani children remained unexplained. In contrast, Black African children were the only ethnic minority group to have significantly fewer socioemotional difficulties. We investigated the role of four indicators of socioeconomic position in explaining these differences and found equivalised household income had the strongest influence on socioemotional difficulties, and that socioeconomic position associations with socioemotional difficulties were less apparent among Pakistani and Bangladeshi children. The association between adverse economic conditions and socioemotional difficulties was partially mediated by maternal psychological distress. In conclusion, unexplained ethnic differences in socioemotional difficulties were seen, with a disadvantage among Pakistani children and an advantage among Black African children. Our results point to the need to address economic deprivation among ethnic minority groups to reduce children's socioemotional difficulties.

The recovery of irradiation damage for Zircaloy-2 and Zircaloy-4 following low dose neutron irradiation at nominally 358 °C

The recovery of irradiation damage in wrought Zircaloy-2 and Zircaloy-4 was determined following a series of post-irradiation anneals at temperatures ranging from 343°C to 510°C and for time periods ranging from 1-h to 500h. The materials had been irradiated at nominally 358°C in the High Flux Isotope Reactor (HFIR) at neutron fluences of nominally 3×1025n/m2 (E>1MeV). Irradiation at nominally 358°C resulted in a coarser distribution of 〈a〉 loops that result in a 25–45% lower irradiation hardening than reported in the literature for irradiations at 260–326°C. The irradiation hardening and recovery were determined using tensile testing at room-temperature. Post-irradiation annealing at 343–427°C was shown to result in an increase in irradiation hardening to values even higher than for the as-irradiated material in the first 1–10h of annealing. This Radiation Anneal Hardening (RAH) was followed by a relatively slow recovery of the irradiation damage. Much faster recovery with no RAH was observed for post-irradiation annealing at temperatures of 454–510°C. Irradiation at 358°C was shown to result in different recovery kinetics than observed in the literature for irradiation at 260–326°C. While the general trend described above is true for the four materials tested (alpha-annealed and beta-treated Zircaloy-2 and Zircaloy-4), notable and yet unexplained differences in RAH and in recovery are observed between the materials that might be a result of differing solute effects. Examinations of microstructure using Transmission Electron Microscopy were used to investigate the RAH and recovery mechanisms. Agreement between the measured and calculated irradiation hardening using a generalized Orowan hardening model to account for the observed loop structure was not as close for the post irradiation annealed condition as for the as-irradiated condition, which can likely be attributed to unaccounted for changes in the configuration of the 〈a〉 loops to dislocation lines, segregation of solutes to dislocation loops, and the potential for the formation of fine clusters of point defects or solutes during annealing.

Sexual orientation–based wage gaps in Australia: The potential role of discrimination and personality

This article reports a research finding that lesbians in Australia earn an unexplained wage premium of 0%–13%, whereas gay men experience an unexplained negative wage gap of 8%–18%. Based on data from the Australian household panel Household Income and Labour Dynamics in Australia, the article is the first to establish these gaps in Australia, and to examine the degree to which credence can be afforded to claims that endowments such as personality traits may help explain such wage differentials. Using ordinary least squares and Blinder–Oaxaca decomposition methods, the study explicitly includes the battery of Big Five personality traits in wage regressions and estimates the contribution of endowments and returns to these traits. The finding is that personality traits and returns to them do not differ along lines of sexual orientation. Gay men in particular suffer a substantial unexplained wage penalty in the workplace. Such unexplained differences suggest that discrimination on the basis of sexual orientation, though unlawful, may exist in Australia.

Why do multi-attribute utility instruments produce different utilities: the relative importance of the descriptive systems, scale and 'micro-utility' effects.

PurposeHealth state utilities measured by the major multi-attribute utility instruments differ. Understanding the reasons for this is important for the choice of instrument and for research designed to reconcile these differences. This paper investigates these reasons by explaining pairwise differences between utilities derived from six multi-attribute utility instruments in terms of (1) their implicit measurement scales; (2) the structure of their descriptive systems; and (3) ‘micro-utility effects’, scale-adjusted differences attributable to their utility formula.Methods The EQ-5D-5L, SF-6D, HUI 3, 15D and AQoL-8D were administered to 8,019 individuals. Utilities and unweighted values were calculated using each instrument. Scale effects were determined by the linear relationship between utilities, the effect of the descriptive system by comparison of scale-adjusted values and ‘micro-utility effects’ by the unexplained difference between utilities and values.ResultsOverall, 66 % of the differences between utilities was attributable to the descriptive systems, 30.3 % to scale effects and 3.7 % to micro-utility effects.DiscussionResults imply that the revision of utility algorithms will not reconcile differences between instruments. The dominating importance of the descriptive system highlights the need for researchers to select the instrument most capable of describing the health states relevant for a study.ConclusionsReconciliation of inconsistent utilities produced by different instruments must focus primarily upon the content of the descriptive system. Utility weights primarily determine the measurement scale. Other differences, attributable to utility formula, are comparatively unimportant.

Extensive dissemination of extended spectrum β-lactamase-producing Enterobacteriaceae in a Dutch nursing home.

Risk factors for rectal carriage of ESBL-E and transmission were investigated in an outbreak of extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL-E). Rectal carriage of ESBL-E was determined in a cross-sectional survey by culture of perianal swabs or fecal samples. Both phenotypical and genotypical methods were used to detect the production of ESBL. Nosocomial transmission was defined as the presence of genotypically related strains in ≥2 residents within the NH. Patient characteristics and variables in infection control practices were registered to investigate risk factors for transmission. A nursing home (NH) in the southern Netherlands. Of 189 residents, 160 residents (84.7%) were screened for ESBL-E carriage. Of these 160 residents, 33 (20.6%) were ESBL-E positive. ESBL carriage rates varied substantially between wards (range, 0-47%). Four different ESBL-E clusters were observed. A bla CTX-M1-15 positive E. coli ST131 constituted the largest cluster (n=21) and was found in multiple wards (n=7). Our investigation revealed extensive clonal dissemination of bla CTX-M1-15-positive E. coli ST131 in a nursing home. Unexplained differences in ESBL prevalence were detected among the wards. As NHs constitute potential sources of multidrug-resistant bacteria, it is important to gain a better understanding of the risks factors and routes of transmission of ESBL-E.