Average Treatment Effects

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G-computation of average treatment effects on the treated and the untreated

G-computation of average treatment effects on the treated and the untreated

In epidemiology, (bio)statistics and related fields, re- searchers are often interested in the average treatment effect in the total population (average treatment effect, ATE). This quantity provides the average difference in outcome between units assigned to the treatment and units assigned to the placebo (control) [1]. However, in economics and evaluation studies, it has been noted that the average treatment effect among units who actually receive the treatment or intervention (average treatment effects on the treated, ATT) may be the implicit quantity sought and the most relevant to policy makers [2]. For instance, consider a scenario where a government has implemented a smoking cessation campaign intervention to decrease the smoking prevalence in a city and now
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Causal Inference Beyond Estimating Average Treatment Effects

Causal Inference Beyond Estimating Average Treatment Effects

Throughout Chapter 2 to 5, we studied three other quantities of interest which are more complicated than the ATE. In Chapter 2, we studied the distributional treatment effects by estimating potential outcome distributions. We showed the limitations of the existing estimation methods, and provided a new nonparametric likelihood method to overcome these limitations. We further developed a theory on the nonparametric BL to test whether a treatment caused any change in the potential outcome distributions. In Chapter 3 and 4, we developed novel approaches of discovering effect modification in a data-driven way while avoiding the issue of using the data twice. More specifically, the CART approach was applied to the absolute treated-minus-control pair differences that do not use treat- ment assignment. The CART method can deal with high-dimensional observational study data, and can efficiently detect effect modification despite the lack of supporting statisti- cal properties. Furthermore, we developed a statistical approach based on multiple testing correction with providing statistical properties. In Chapter 6, we established a theory of the MAFF in causal inference. We elucidated the causal definition of the MAFF using the potential outcome framework and developed a method to estimate the MAFF from the data. We delineated potential measurement error scenarios and the problems that arise in the presence of such measurement errors. To obtain an unbiased estimate of the MAFF, we developed a novel maximum likelihood estimation method to incorporate the potential measurement errors based on exponential family g-modeling.
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Transformative treatments

Transformative treatments

In response, in order to allow the world to provide an answer, scientists change the question. Instead of asking a question about an individual, they ask a question about a group. They replace the estimation of individual treatment effects with average treatment effects. 4 Focusing on the counterfactual problem of observing both treated and untreated states, scholars have developed sophisticated frameworks to estimate average treatment effects across groups of subjects given what we can observe in the actual world (Rubin 2005, Pearl 2009). Researchers attempt to create comparison classes for causal inferences using similar populations, such that, despite internal heterogeneity at the level of the individual, the populations may be considered to be duplicates (with respect to the properties of interest), at the group level. The comparison classes for causal inferences use properties of groups rather than properties of individuals and their nonactual, duplicate counterparts, and report average effects rather than individual effects.
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Nonparametric estimation of ATE and QTE: an application of Fractile Graphical Analysis

Nonparametric estimation of ATE and QTE: an application of Fractile Graphical Analysis

In some cases, we are interested not only on the average effect but on the effect on a sub-group of the population. Average treatment effects do not fully describe all the distributional features of the W-treatment. For instance, high ability individuals may benefit differently from program par- ticipation than low ability ones, even if they have the same value of covariates. This determines that the effect of a certain treatment would vary according to unobservable characteristics. A parameter of interest in the presence of heterogeneous treatment effects is the quantile treatment effect (QTE). As originally defined in Docksum (1974) and Lehmann (1974), the QTE cor- responds, for any fixed percentile, to the horizontal distance between two cumulative distribution functions. Let F 0 and F 1 be the control and treated
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Partial identification of the distribution of treatment effects and its confidence sets

Partial identification of the distribution of treatment effects and its confidence sets

Evaluating the effect of a treatment or a social program is important in diverse disciplines including the social and medical sciences. The central problem in the evaluation of a treatment is that any potential outcome that program participants would have received without the treatment is not observed. Because of this missing data problem, most work in the treatment effect literature has focused on the evaluation of various average treatment effects such as the mean of treatment effects. See Lee (2005), Abbring and Heckman (2007), Heckman and Vytlacil (2007a, 2007b) for discussions and references. However, empirical evidence strongly suggests that treatment effect heterogeneity prevails in many experiments and various interesting effects of the treatment are missed by the average treatment effects alone. See Djebbari and Smith (2008) who studied heterogeneous program impacts in social experiments such as PROGRESA; Black, Smith, Berger, and Noel (2003) who evaluated the Worker Profiling and Reemployment Services system; and Bitler, Gelbach, and Hoynes (2006) who studied the welfare effect of the change from Aid to Families with Dependent Children (AFDC) to Temporary Assistance for Needy Families (TANF) programs. Other work focusing on treatment effect heterogeneity includes Heckman and Robb (1985), Manski (1990), Imbens and Rubin (1997), Lalonde (1995), Dehejia (1997), Heckman and Smith (1993), Heckman, Smith, and Clements (1997), Lechner (1999), and Abadie, Angrist, and Imbens (2002).
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Investigations on the emulsifying properties of egg white protein : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Auckland, New Zealand

Investigations on the emulsifying properties of egg white protein : a thesis presented in partial fulfilment of the requirements for the degree of Master of Food Technology at Massey University, Auckland, New Zealand

In another part of the study, the effects of enzyme type (bromelain, ficin and papain), enzyme concentration (0.3, 0.5, 1, 2 and 4% w/w; enzyme/substrate (E/S) ratio) and hydrolysis time (0, 30, 60 and 120 minutes) on the degree of hydrolysis (DH) of EWP were investigated by diluting EWL containing 10% EWP to different EWP concentrations followed by adding enzymes into the EWL solutions. DH was observed to increase significantly (p < 0.05) with increasing enzyme concentration and hydrolysis time. A significant difference (p < 0.05) among the different types of enzymes was only observed from the samples with 4% E/S ratio at 120 minutes of hydrolysis time. Papain yielded the highest DH of 7.69% while bromelain and ficin yielded similar DH levels of 5.03% and 4.99%, respectively. The results of SDS-PAGE revealed that the protein bands corresponding to ovalbumin and ovotransferrin disappeared due to their enzymatic hydrolysis into smaller peptides but it was not significantly different between the samples treated with different E/S ratios and hydrolysis reaction times.
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Study on the effects of blueberry treatment on histone acetylation modification of CCl-induced liver disease in rats.

Study on the effects of blueberry treatment on histone acetylation modification of CCl-induced liver disease in rats.

was calculated, hematoxylin-eosin staining was conducted, and H3K9, H3K14, and H3K18 expressions were evaluated among the nuclear proteins of the liver tissues. No differences in alanine transaminase were noted between the control and intervention groups, but significant differences were detected among the model, treatment, and natural recovery groups (P < 0.01). Significant differences were also observed in aspartate transaminase, hyaluronic acid, and collagen IV among the model, treatment, intervention, and natural recovery groups (P < 0.01, P < 0.01, P < 0.01). Liver index, and H3K9 and H3K14 expression were significantly different among the model groups (P < 0.05 and P < 0.01), whereas H3K18 expression was dramatically different among model, treatment, intervention, and natural recovery groups (P < 0.01). Following blueberry treatment, rat liver function and hepatic fibrosis improved, potentially indicating that blueberry components could regulate histone acetylation and improve liver pathologic changes in rats with CCl 4 -induced disease.
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An examination of airline pricing : testing the effects of mergers and uncertainty on average fare and dispersion

An examination of airline pricing : testing the effects of mergers and uncertainty on average fare and dispersion

dispersion to arise, bringing up the obvious point that, even in situations of demand certainty, predictable, widespread, welfare-enhancing dispersion will occur. Evidence abounds to this effect: pizzerias, movie theaters, cell phone service, and even airlines are a few examples. In each situation, the producer’s desire to siphon price elastic consumers away from peak periods in which demand cannot be fully satisfied to off-peak periods in which capacity is underutilized is driven by the goal of increasing profits. Among the many effects of this process is greater price dispersion. Few would argue, however, that consumers are worse off as a result. If Dana is correct, what he has introduced is ultimately an extension of our knowledge of price dispersion theory: any dispersion occurring for whatever reason may be exacerbated by uncertainty facing suppliers of costly, perishable goods. 57
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Effect of different Gamma radiation doses on the growing of the Achmrar local fig variety Ficus carica L. in Morocco

Effect of different Gamma radiation doses on the growing of the Achmrar local fig variety Ficus carica L. in Morocco

It was evident from the results that different Gamma radiation doses applied had significant effects on the vegetative development parameters of the bud cutting. Increased Gamma radiation treatments resulted in decrease on vegetative development of bud cutting. It was determined that 62Gy Gamma radiation doses are suitable for Achmrar fig variety whereas 80 and 100 Gy radiation dose have many negative effects on the plants. These results give some information in determining appropriate dose levels on mutations breeding studies in other fig varieties.
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Testing and modelling market microstructure effects with an application to the Dow Jones industrial average

Testing and modelling market microstructure effects with an application to the Dow Jones industrial average

For all the periods in which we reject the null hypothesis of no market microstructure effects, we then test H 0 $ versus H A $ , defined respectively in (12) and (13), using the statistic suggested in (14). We perform two sequences of test, the first one conditional on rejecting the null of no microstructure using the test statistic in (9) and the second conditional on the same outcome using the statistic in (11). The results are reported in Table 4, columns 2 to 5, and the plots are given in Figures 3 and 4. It is immediate to see that the null hypothesis is rejected in almost all the cases. This provides strong evidence that while the presence of microstructure induces a severe bias when estimating volatility using high frequency data, such a bias grows less than linearly in the number of intraday observations. In fact, given (6), acceptance of the null hypothesis would imply that
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The Effects of the 2008 Health Reform on Out of Pocket Health Expenditures in Turkey

The Effects of the 2008 Health Reform on Out of Pocket Health Expenditures in Turkey

Healthcare in many developing countries, including those in Middle East and North Africa (MENA) region, is mainly funded and financed through out-of-pocket expenditures (OOPEs) by households (Akinci et al., 2014). OOPEs is a part of the private health expenditures which includes in-kind payments and perks to suppliers of pharmaceutical products, therapeutic appliances and other health related goods and services to health practitioners with purpose the enhancement of the individuals’ health status (Garg and Karan, 2009). An important policy for a country’s health care system is to provide financial protection from extreme OOPEs to assure impartial access to health care. In the absence of this policy, a household may be forced to spend large amounts on medical bills and treatment, and significant part of its time to treat and take care of a family member. OOPEs is of major concern for the policy makers, because of their multiple consequences to the household, the ill family members and the society overall.
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Hyperbolic Transformation and Average Elasticity in the Framework of the Fixed Effects Logit Model

Hyperbolic Transformation and Average Elasticity in the Framework of the Fixed Effects Logit Model

adjusted estimators, which is available in nonlinear panel data models and aims at the reduction of time-series finite sample bias (i.e. the approximately unbiased estimation of the incidental parameters as well as the parameters of interest, leading to obtaining the approximate marginal effects). Various approaches are proposed in line with the bias-adjustment: Hahn and Newey (2004) [8], Cox and Reid (1987) [9], Lancaster (2002) [10], Arellano (2003) [11], Arellano and Bonhomme (2009) [12], Carro (2007) [13], Fernández-Val (2009) [14], Severini (1998) [15], Pace and Salvan (2006) [16], Bester and Hansen (2009) [17], etc. Some of the approaches are reviewed in Arellano and Hahn (2007) [18] and Hsiao (2010) [19]. However, author’s policy is to conduct the consistent estimation for the case of small time dimension and therefore this paper is not bent upon the bias-adjusted estimators.
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Impacts of reduced bird densities on pollination and dispersal mutualisms in New Zealand forests : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Ecology at Massey University

Impacts of reduced bird densities on pollination and dispersal mutualisms in New Zealand forests : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Ecology at Massey University

ANOV A of the effects of site, tree, treatment, site*treatment interaction on the number of pollen grains deposited on stigmas of G.. ANOVA of the effects of site, tree, treatment, site*[r]

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On the average degree eigenvalues and average degree energy of graphs

On the average degree eigenvalues and average degree energy of graphs

Conclusion. In the present paper, the concepts of average degree matrix, average degree eigenvalues and average degree energy of a graph are given and studied. In the literature the degree sum matrix [5] of a graph, in which diagonal entries are zero, exists, whereas in average degree matrix introduced here, the diagonal entries are not necessarily zeros. Hence the results obtained in this paper for average degree matrix are not overlapping with the results of degree sum matrix.

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The effects of surgical treatment with chondroblastoma in children and adolescents in open epiphyseal plate of long bones

The effects of surgical treatment with chondroblastoma in children and adolescents in open epiphyseal plate of long bones

Chondroblastoma is a benign tumor and mostly originates in an epiphyseal plate of long bone, which primarily occurs in children and adolescents. Previous studies reported first-line treatment should be lesion curettage [1, 9, 12, 13]. Local recurrence rate of lesion curettage was 10~35%. Risk factors of recurrence include location, young age, inadequate surgery, and biologic aggressiveness of tumor [12, 13]. Schreuder et al. reported that surgical technique might play the most important role in chondrobla- soma recurrence [12]. Some reports showed that simple curettage was associated with higher recurrence rate because of too much worry about damaging an open epiphyseal plate [12, 13]. In this study, we preferred to use a bone drill to polish tumor cavity. With our experience, 2 mm of latent lesion, 3 mm of active, and 3–5 mm of aggressive were appropriate to remove residual tumor cells. We also took chemical (95% alcohol) and thermal (elec- trotome) methods to inactivate tumor cavity. However, in areas near or crossing the epiphyseal line, we would open a small cortical window to remove tumor, which could minimize the epiphyseal line being injured. Besides, using a bone drill was relatively conservative, while chemical and thermal methods were more radical. Thus, those pre- processing techniques could prevent tumor recurrence drastically and reduce epiphyseal plate damage.
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Assessing the outcomes of implantable cardioverter defibrillator treatment in a real world setting: results from hospital record data

Assessing the outcomes of implantable cardioverter defibrillator treatment in a real world setting: results from hospital record data

In this study, ICD treatment was associated with signifi- cantly lower mortality, slightly higher re-hospitalization rate and significantly higher regional expenditure. In our sam- ple, mortality at 1 year was reduced by between 9% and 10%, with a relative risk reduction of 0.59. The hazard ratios for the two subsamples were 0.80 and 0.85, respectively. These findings are in line with those reported from RCTs and collected in recent reviews, though direct comparisons should be made with caution, considering the different study designs [18]. A more significant difference is observed in comparison with the results obtained from a meta- analysis of other observational studies in which ICDs re- duced all-cause mortality by 46% (CI, 32% to 57%) [7]. This greater difference can be partially explained by the high het- erogeneity of the studies selected for this review. Indeed, among 11 observational studies with a contemporaneous control group, only two can be compared with our present study in terms of sample size and the method used to de- termine the benefits of ICDs [19,20]. In line with our find- ings, the relative risk reduction in all-cause mortality in these two studies was 0.67 (CI 0.63–072 ) and 0.71 (CI 0.51–0.97), respectively.
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REPORT BY THE LONDON DRUG AND ALCOHOL NETWORK ON ALCOHOL TREATMENT N LONDON

REPORT BY THE LONDON DRUG AND ALCOHOL NETWORK ON ALCOHOL TREATMENT N LONDON

The London Alcohol Statistics Project found that NDTMS-type alcohol data enables some interesting comparison of treatment activity between providers, and also, in theory, between alcohol and drug treatment. There are, however, a number of important limitations to its usefulness. The data does not describe the complexity of cases, the level of input from the alcohol service, or any changes in the client that may take place. Also, great care needs to be taken in making direct comparisons between service providers who may offer very different interventions, and/or target different population groups.
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Adverse effects of mefloquine for the treatment of uncomplicated malaria in Thailand: A pooled analysis of 19, 850 individual patients

Adverse effects of mefloquine for the treatment of uncomplicated malaria in Thailand: A pooled analysis of 19, 850 individual patients

Mefloquine (MQ) has been used for the treatment of malaria since the mid-1980s, first as monotherapy or as fixed combination with sulfadoxine-pyrimethamine (MSP) and since the mid-1990s in combination with artesunate. There is a renewed interested in MQ as part of a triple therapy for the treatment of multi-drug resistance P. falciparum malaria. The wide- spread use of MQ beyond south-East Asia has been constrained by reports of poor tolerabil- ity. Here we present the side effect profile of MQ for the treatment of uncomplicated malaria on the Thai-Myanmar/Cambodia borders. In total 19,850 patients received seven different regimens containing either 15 or 24–25 mg/kg of MQ, the latter given either as a single dose, or split over two or three days. The analysis focused on (predominantly) gastrointesti- nal and neuropsychiatric events as compared to the new fixed dose combination of MQ plus artesunate given as equal doses of 8 mg/kg MQ per day over three days. Gastrointestinal side effects were dose-dependent and associated with the severity of malaria symptoms. Serious neuropsychiatric side effects associated with MQ use were rare: for a single 25 mg/ kg dose it was 11.9 per 10,000 treatments (95% confidence interval, CI, 4–285) vs. 7.8 (3– 15) for the 15 mg/kg dose. The risk with 25 mg/kg was much higher when it was given as repeat dosing in patients who had failed treatment with 15 mg/kg MQ in the preceding month; (RR 6.57 (95% CI 1.33 to 32.4), p = 0.0077). MQ was best tolerated as 15 mg/kg or as 24 mg/kg when given over three days in combination with artesunate. We conclude that the tolerance of a single dose of MQ in the treatment of uncomplicated malaria is moderate, but can be improved by administering it as a split dose over three days.
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Gene Expression Changes with Minor Effects on the Population Average Have Major Effects on the Occurrence of Cells with Extreme Protein Concentrations

Gene Expression Changes with Minor Effects on the Population Average Have Major Effects on the Occurrence of Cells with Extreme Protein Concentrations

We have demonstrated that the fraction of cells in a population that has an extremely high or low protein level is remarkably sensitive to changes in the protein production parameters that do not affect the mean protein level of the population much. When the mean protein level is changed by a transcriptional or translational regulation by 50%, the fraction of the cells in the rare state can easily change by several orders of magnitude. This insight underscores a need to consider the potentially large effects on the tails of a distribution of cells, when a weak regulatory effect on the population average is observed, if the cells in the tail of the distribution have an interesting phenotype.
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EFFECT OF CERTAIN AYURVEDIC DRUGS ON VITILIGO (SWITRA) IN CHILDREN .......

EFFECT OF CERTAIN AYURVEDIC DRUGS ON VITILIGO (SWITRA) IN CHILDREN .......

gave pro-dermal symptoms of itching at the place where patch was developed later. This could be due to Viruddha ahara alone invoking auto-immunological re- sponse.The Lakshanas of Doshaja Switra, as mentioned in classics were not found in the patients taken for the study.Early im- provement is seen if Visphota is developed on application of lepa.Improvement is ear- lier if re-pigmentation starts with pig- mented spots which later configured to normal skin colour, when compared to re- pigmentation, which occurs from peri- phery to centre.The pigmentation process is earlier in small patches when compared to bigger one.Patches having white hairs responded late to treatment.The patches over the outer border of palm and sole re- spond quickly to treatment.The improve- ment could be earlier if tyrosine rich diet is given to the patients.Placebo group who had undergone Shodhana once (Virecha- na) after Pachana, Snehana and Swedana did not show any improvement; hence, Vi- rechana alone may not help in treating switra. However, it needs a further study to find as to whether repeated Shodhana helps in Switra or not.Local treatment is found to be more effective after Shodhana Chikitsa in the present study. It is possible that local application even without Sodha- na may help in treating the Switra; howev- er, this also needs further study.The same drug compound if continued for longer time may give much better results.
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