Assigning and combining probabilities in single-case studies

There is currently a considerable diversity of quantitative measures available for summarizing the results in single-case studies. Given that the interpretation of some of them is difficult due to the lack of established benchmarks, the current paper proposes an approach for obtaining further numerical evidence on the importance of the results, complementing the substantive criteria, visual analysis, and primary summary measures. This additional evidence consists of obtaining the statistical significance of the outcome when referred to the corresponding sampling distribution. This sampling distribution is formed by the values of the outcomes (expressed as data nonoverlap, R-squared, etc.) in case the intervention is ineffective. The approach proposed here is intended to offer the outcome"s probability of being as extreme when there is no treatment effect without the need for some assumptions that cannot be checked with guarantees. Following this approach, researchers would compare their outcomes to reference values rather than constructing the sampling distributions themselves. The integration of single-case studies is problematic, when different metrics are used across primary studies and not all raw data are available. Via the approach for assigning p values it is possible to combine the results of similar studies regardless of the primary effect size indicator. The alternatives for combining probabilities are discussed in the context of single-case studies pointing out two potentially useful methods one based on a weighted average and the other on the binomial test.

Comparing potentially avoidable hospitalization rates related to ambulatory care sensitive conditions in Switzerland: the need to refine the definition of health conditions and to adjust for population health status.

BACKGROUND: Regional rates of hospitalization for ambulatory care sensitive conditions (ACSC) are used to compare the availability and quality of ambulatory care but the risk adjustment for population health status is often minimal. The objectives of the study was to examine the impact of more extensive risk adjustment on regional comparisons and to investigate the relationship between various area-level factors and the properly adjusted rates. METHODS: Our study is an observational study based on routine data of 2 million anonymous insured in 26 Swiss cantons followed over one or two years. A binomial negative regression was modeled with increasingly detailed information on health status (age and gender only, inpatient diagnoses, outpatient conditions inferred from dispensed drugs and frequency of physician visits). Hospitalizations for ACSC were identified from principal diagnoses detecting 19 conditions, with an updated list of ICD-10 diagnostic codes. Co-morbidities and surgical procedures were used as exclusion criteria to improve the specificity of the detection of potentially avoidable hospitalizations. The impact of the adjustment approaches was measured by changes in the standardized ratios calculated with and without other data besides age and gender. RESULTS: 25% of cases identified by inpatient main diagnoses were removed by applying exclusion criteria. Cantonal ACSC hospitalizations rates varied from to 1.4 to 8.9 per 1,000 insured, per year. Morbidity inferred from diagnoses and drugs dramatically increased the predictive performance, the greatest effect found for conditions linked to an ACSC. More visits were associated with fewer PAH although very high users were at greater risk and subjects who had not consulted at negligible risk. By maximizing health status adjustment, two thirds of the cantons changed their adjusted ratio by more than 10 percent. Cantonal variations remained substantial but unexplained by supply or demand. CONCLUSION: Additional adjustment for health status is required when using ACSC to monitor ambulatory care. Drug-inferred morbidities are a promising approach.

Distribuição espacial de Toxoptera citricida (Kirkaldy) (Hemiptera: Aphididae) na cultura de citros

O estudo da distribuição espacial de pragas é fundamental para elaboração de planos de amostragem para o uso do manejo integrado de pragas. Para o afídeo Toxoptera citricida (Kirkaldy), estudou-se a distribuição espacial em talhões de pomares de citros comerciais de laranja-doce [Citrus sinensis (L.) Osbeck] da variedade Pêra, com 5; 9 e 15 anos de idade, durante o período de setembro de 2004 a abril de 2005. Foram realizadas 14 amostragens de número de T. citricida em intervalos aproximados de 15 dias entre as mesmas, utilizando-se de armadilhas adesivas de cor amarela (0,11 x 0,11 m) fixadas à planta, a 1,5 m de altura aproximadamente. As armadilhas foram distribuídas na área, a cada cinco plantas na linha, em linhas alternadas, totalizando 137 armadilhas no talhão com 5 anos, 140 no talhão com 9 anos e 80 no talhão com 15 anos. Os índices de dispersão utilizados foram: razão variância média (I), índice de Morisita (Idelta), coeficiente de Green (Cx) e expoente k da distribuição Binomial Negativa. O índice que melhor representou a agregação do pulgão foi o expoente k da distribuição Binomial Negativa, e a distribuição binomial negativa foi o modelo que melhor se ajustou aos dados. Através destas análises, verificou-se que a maioria das amostragens apresentou uma distribuição agregada da população de T. citricida.

Predicción de la densidad de pulgones en alfalfa a partir de un muestreo presencia-ausencia

La estimación de la media de la densidad de pulgones en alfalfa basada en conteos de campo se compara con el muestreo presencia-ausencia. Se obtuvieron 21 muestras aleatorias formadas por 75 tallos obtenidos en campos comerciales de alfalfa en Lleida (valle del Ebro) con el objetivo de predecir la estimación de la densidad media de pulgones (û) a partir de la estimación de la proporción de tallos infestados (p). La relación empírica entre û y su varianza muestral utilizando como modelo la ley potencial de Taylor es satisfactoria (r2 = 0,98). La relación empírica entre p y su varianza muestral es prácticamente binomial. Finalmente, la relación empírica entre û y p a partir de la regresión lineal entre ln(û) y ln(-ln p) fue satisfactoria (r2 = 0,94). A partir del muestreo presencia-ausencia es posible estimar densidades medias de pulgones de hasta unos 20 pulgones por tallo.

Biopolítica de Estados expulsores

La biopolítica sobre los migrantes se fundamenta en el binomio dejar entrar-residir o expulsar. Las leyes de extranjería están elaboradas sobre dos ejes: por un lado, en la regulación de los flujos migratorios en función del mercado de trabajo y las demandas de la economía y, por otro, en el control policial y la persecución de la inmigración irregular. Para la realización del primer eje del binomio, dejar entrar y residir, los Estados se dotan de mecanismos de regulación e intervención sobre el inmigrante concebido como fuerza de trabajo productiva. Asimismo los Estados crean mecanismos de control-sanción para las personas migrantes que incumplen los requisitos establecidos para entrar y residir en el territorio. En este punto la biopolítica sobre la población migrante se solapa o toma forma en el ejercicio de la soberanía por el Leviatán. Las medidas de control y sanción que los gobiernos ponen en marcha sobre los sin papeles han creado una imponente maquinaria de coacción en el interior de las instituciones del Estado de derecho hasta el punto de convertirlo en un Estado expulsor.

Alcohol expectancies and alcohol outcomes: effects of the use of protective behavioral strategies.

OBJECTIVE: Alcohol expectancies (AEs) are positively associated with drinking behaviors, whereas the use of protective behavioural strategies (PBS) is negatively related to alcohol outcomes among young adults. PBS have been shown to weaken relationships between some alcohol risk factors and alcohol outcomes. This study aimed to examine longitudinally the moderating effect of PBS on the relationships between AEs and alcohol outcomes among young adults. METHOD: Participants (N = 188; 61.7% female) were U.S. young adults participating in a larger longitudinal study. Measures of PBS, AEs, alcohol use, and related consequences were used from the baseline and 12-month follow-up assessments. RESULTS: Negative binomial hurdle models found that PBS (total score) significantly moderated the relationship between positive AEs and consequences, such that among high school seniors endorsing higher positive AEs, those using more PBS in high school reported fewer negative consequences 1 year later. PBS (Manner of Drinking) also moderated the relationship between negative AEs and alcohol use, revealing the use of PBS in high school as having a protective function against later drinking among participants with high positive AEs. Last, PBS (Serious Harm Reduction) significantly moderated the associations between positive AEs and alcohol use and between negative AEs and consequences, such that participants with higher AEs and higher PBS use in high school were at greatest risk for drinking and experiencing negative consequences later. CONCLUSIONS: Overall, these findings suggest that PBS use may be protective by weakening relationships between positive AEs and alcohol outcomes. Limitations and future directions are discussed.

Health care usage among immigrants and native-born elderly populations in eleven European countries: results from SHARE

Differences in health care utilization of immigrants 50 years of age and older relative to the native-born populations in eleven European countries are investigated. Negative binomial and zero-inflated Poisson regression are used to examine differences between immigrants and native-borns in number of doctor visits, visits to general practitioners, and hospital stays using the 2004 Survey of Health, Ageing, and Retirement in Europe database. In the pooled European sample and in some individual countries, older immigrants use from 13 to 20% more health services than native-borns after demographic characteristics are controlled. After controlling for the need for health care, differences between immigrants and native-borns in the use of physicians, but not hospitals, are reduced by about half. These are not changed much with the incorporation of indicators of socioeconomic status and extra insurance coverage. Higher country-level relative expenditures on health, paying physicians a fee-for-service, and physician density are associated with higher usage of physician services among immigrants.

Geometric stopping of a random walk and its applications to valuing equity-linked death benefits

We study discrete-time models in which death benefits can depend on a stock price index, the logarithm of which is modeled as a random walk. Examples of such benefit payments include put and call options, barrier options, and lookback options. Because the distribution of the curtate-future-lifetime can be approximated by a linear combination of geometric distributions, it suffices to consider curtate-future-lifetimes with a geometric distribution. In binomial and trinomial tree models, closed-form expressions for the expectations of the discounted benefit payment are obtained for a series of options. They are based on results concerning geometric stopping of a random walk, in particular also on a version of the Wiener-Hopf factorization.

Reaalioptioiden ja binomimallm hyväksikäyttö strategisten tutkimus ja tuotekehitysinvestointien arvioimisessa

Tutkielman tavoitteena oli tutkia ja analysoida kirjallisuuden pohjalta reaalioptioteoriaa ja reaalioptioiden arvonmääritystapana binomimallia. Erityisenä painona tutkimuksessa oli reaalioptioiden hyväksikäyttö strategiaan ja tutkimus- ja tuotekehitysinvestointeihin. Tutkielma on toteutettu kirjallisuustutkimuksena. Tutkimusmetodologia on käsiteanalyyttinen. Lähdeaineistona on käytetty ulkomaisia tieteellisen aikakausijulkaisujen artikkeleita ja reaalioptioihin liittyviä kirjoja. Tutkielman tarkoituksena oli keskittyä reaalioptioteorian ja binomimallin ymmärtämiseen, perusteisiin ja käsitteistöön. Reaalioptiot tuovat hankkeiden arvonmääritykseen joustavuuden komponentin. Nykyajan kilpailullisilla markkinoilla on lisääntyvässä määrin epävarmuutta. Epävarmuuden hyödyntäminen on reaalioptioajattelun lähtökohta. Binomimalli on yksi tapa määrittää arvo reaalioptioille ja tähän malliin paneudutaan tutkielmassa syvemmin.

Social factors related to the clinical severity of influenza cases in Spain during the A(H1N1)2009 virus pandemic

Background During the 2009 influenza pandemic, a change in the type of patients most often affected by influenza was observed. The objective of this study was to assess the role of individual and social determinants in hospitalizations due to influenza A (H1N1) 2009 infection. Methods We studied hospitalized patients (cases) and outpatients (controls) with confirmed influenza A (H1N1) 2009 infection. A standardized questionnaire was used to collect data. Variables that might be related to the hospitalization of influenza cases were compared by estimation of the odds ratio (OR) and 95% confidence intervals (CI) and the variables entered into binomial logistic regression models. Results Hospitalization due to pandemic A (H1N1) 2009 influenza virus infections was associated with non-Caucasian ethnicity (OR: 2.18, 95% CI 1.17 − 4.08), overcrowding (OR: 2.84, 95% CI 1.20 − 6.72), comorbidity and the lack of previous preventive information (OR: 2.69, 95% CI: 1.50 − 4.83). Secondary or higher education was associated with a lower risk of hospitalization (OR 0.56, 95% CI: 0.36 − 0.87) Conclusions In addition to individual factors such as comorbidity, other factors such as educational level, ethnicity or overcrowding were associated with hospitalization due to A (H1N1) 2009 influenza virus infections.

Independent and combined associations of risky single-occasion drinking and drinking volume with alcohol use disorder: Evidence from a sample of young Swiss men.

BACKGROUND: Risky single-occasion drinking (RSOD) is a prevalent and potentially harmful alcohol use pattern associated with increased alcohol use disorder (AUD). However, RSOD is commonly associated with a higher level of alcohol intake, and most studies have not controlled for drinking volume (DV). Thus, it is unclear whether the findings provide information about RSOD or DV. This study sought to investigate the independent and combined effects of RSOD and DV on AUD. METHODS: Data were collected in the longitudinal Cohort Study on Substance Use Risk Factors (C-SURF) among 5598 young Swiss male alcohol users in their early twenties. Assessment included DV, RSOD, and AUD at two time points. Generalized linear models for binomial distributions provided evidence regarding associations of DV, RSOD, and their interaction. RESULTS: DV, RSOD, and their interaction were significantly related to the number of AUD criteria. The slope of the interaction was steeper for non/rare RSOD than for frequent RSOD. CONCLUSIONS: RSOD appears to be a harmful pattern of drinking, associated with increased AUD and it moderated the relationship between DV and AUD. This study highlighted the importance of taking drinking patterns into account, for both research and public health planning, since RSO drinkers constitute a vulnerable subgroup for AUD.

Evidence on the role of ownership structure on firms' innovative performance

Based on the Knowledge Production Function framework given by Griliches -1979-, we slightly modify it so that the innovative output depends upon a set of factors related to the firm internal characteristics and are influenced by the environment. Specifically, regarding the firm internal determinants the effect of the concentration of the ownership, the composition of the boards of directors and the effect of the nature of the ownership (foreign and public) are analyzed. Additionally, in order to capture the determinants of the environment in which the firm operates other variables concerning the internationalization of market, the agglomeration economies and the regional knowledge externalities are also considered. In order to assess the impact of these determinants on the number of patents and models of use awarded by the firm, the discreteness of the latter variable has to be taken into account. We apply Poisson and Negative Binomial models for a more comprehensive evaluation of the hypothesis in a panel of Spanish manufacturing firms. The results show patenting activity is positively favoured by being located in an environment with a high innovative activity, due to the existence of knowledge spillovers and agglomeration economies.

Health care utilization among immigrants and native-born populations in 11 European countries. Results from the Survey of Health, Ageing and Retirement in Europe

This study examines health care utilization of immigrants relative to the native-born populations aged 50 years and older in eleven European countries. Methods. We analyzed data from the Survey of Health Aging and Retirement in Europe (SHARE) from 2004 for a sample of 27,444 individuals in 11 European countries. Negative Binomial regression was conducted to examine the difference in number of doctor visits, visits to General Practitioners (GPs), and hospital stays between immigrants and the native-born individuals. Results: We find evidence those immigrants above age 50 use health services on average more than the native-born populations with the same characteristics. Our models show immigrants have between 6% and 27% more expected visits to the doctor, GP or hospital stays when compared to native-born populations in a number of European countries. Discussion: Elderly immigrant populations might be using health services more intensively due to cultural reasons.

Assigning and combining probabilities in single-case designs: A second study

The present study builds on a previous proposal for assigning probabilities to the outcomes computed using different primary indicators in single-case studies. These probabilities are obtained comparing the outcome to previously tabulated reference values and reflect the likelihood of the results in case there was no intervention effect. The current study explores how well different metrics are translated into p values in the context of simulation data. Furthermore, two published multiple baseline data sets are used to illustrate how well the probabilities could reflect the intervention effectiveness as assessed by the original authors. Finally, the importance of which primary indicator is used in each data set to be integrated is explored; two ways of combining probabilities are used: a weighted average and a binomial test. The results indicate that the translation into p values works well for the two nonoverlap procedures, with the results for the regression-based procedure diverging due to some undesirable features of its performance. These p values, both when taken individually and when combined, were well-aligned with the effectiveness for the real-life data. The results suggest that assigning probabilities can be useful for translating the primary measure into the same metric, using these probabilities as additional evidence on the importance of behavioral change, complementing visual analysis and professional's judgments.

Epidemiologia comparativa da podridão negra e da alternariose do repolho no Agreste de Pernambuco

A podridão negra causada por Xanthomonas campestris pv. campestris, e a alternariose causada por Alternaria brassicicola constituem importantes doenças do repolho no estado de Pernambuco. Em virtude do desconhecimento sobre a epidemiologia dessas doenças a nível regional, foi efetuada a análise comparativa das epidemias com ênfase nos aspectos temporais e espaciais, em 1997 e 1998, cada ano em uma área de plantio diferente, localizadas no município de Camocim de São Félix, Agreste de Pernambuco. Em cada área, a intervalos semanais, foram avaliadas 1.920 plantas quanto à incidência e severidade das duas doenças, bem como efetuado o mapeamento espacial de plantas assintomáticas e sintomáticas. Os valores iniciais (y o) e máximos (y max) de incidência e severidade, as taxas estimadas de progresso da doença (k) e as áreas abaixo das curvas de progresso das doenças (AACPD), apresentaram pequena variação entre as doenças, sendo as diferenças mais evidentes entre os anos de plantio. As maiores intensidades das doenças foram observadas em 1998, uma vez que próximo à área de plantio havia grande quantidade de plantas e restos culturais infetados, o que não ocorreu em 1997. Pelas análises de "ordinary runs", ajuste à distribuição beta-binomial e autocorrelação espacial, na maioria das situações, foi constatado um arranjo aleatório de plantas doentes nas avaliações iniciais, evoluindo posteriormente para um arranjo agregado, indicando que as doenças podem ter sido originadas de aloinfecções pela chegada de inóculo externo, seguidas de autoinfecções decorrentes da disseminação planta-a-planta.