Project STAR Research Articles

Design of Project STAR: A randomized controlled trial evaluating the impact of an adaptive intervention on long-term weight-loss maintenance

BackgroundWithout provision of additional intervention, most individuals regain weight after the end of weight-loss programs. Extended-care programs have been demonstrated to improve long-term weight-loss maintenance, but effects are modest. MethodsWe proposed to evaluate whether delivering extended-care telephone sessions on an ADAPTIVE (provided when individuals are deemed to be at high-risk for weight regain) versus STATIC (the once-per-month schedule typically used in extended-care programs) schedule improves weight regain after initial weight loss. Adults with obesity were initially recruited for a 16-week lifestyle weight-loss program, and those who lost ≥5 % of their initial weight were eligible for enrollment in the Project STAR maintenance trial. ResultsA total of 449 individuals (mean ± SD age = 49.5 ± 11.4 years, BMI = 35.7 ± 4.0 kg/m2, 83.5 % female, 23.4 % Black or African American, 9.8 % Hispanic) were recruited for the initial weight-loss program and lost an average of 6.4 ± 4.9 % of their initial body weight; 255 were randomized to the maintenance trial. There were no significant differences between participants randomized to the trial versus those who were not in terms of baseline weight, gender, race/ethnicity, education, or marital status, all ps > 0.05; however, participants who were randomized to the trial were older, p = .014, and reported higher incomes, p < .001. ConclusionResults from Project STAR will demonstrate whether providing extended-care intervention on an individually adaptable schedule improves long-term weight-loss maintenance. Moreover, the rich longitudinal dataset collected during the trial will serve as a foundation for building future predictive algorithms of weight regain and novel weight-maintenance interventions.

The effect of smaller classes on infection-related school absence: evidence from the Project STAR randomized controlled trial

BackgroundIn an effort to reduce viral transmission, many schools reduced class sizes during the recent pandemic. Yet the effect of class size on transmission is unknown.MethodsWe used data from Project STAR, a randomized controlled trial in which 10,816 Tennessee elementary students were assigned at random to smaller classes (13 to 17 students) or larger classes (22 to 26 students) in 1985-89. We merged Project STAR schools with data on local deaths from pneumonia and influenza in the 122 Cities Mortality Report System. Using mixed effects linear, Poisson, and negative binomial regression, we estimated the main effect of smaller classes on absence. We used an interaction to test whether the effect of small classes on absence was larger when and where community pneumonia and influenza prevalence was high.ResultsSmall classes reduced absence by 0.43 days/year (95% CI -0.06 to -0.80, p < 0.05), but small classes had no significant interaction with community pneumonia and influenza mortality (95% CI -0.27 to + 0.30, p > 0.90), indicating that the reduction in absence due to small classes was not larger when community disease prevalence was high.ConclusionSmall classes reduced absence, but the reduction was not larger when disease prevalence was high, so the reduction in absence was not necessarily achieved by reducing infection. Small classes, by themselves, may not suffice to reduce the spread of respiratory viruses.

Inference on optimal treatment assignments

We consider inference on optimal treatment assignments. Our methods allow inference on the treatment assignment rule that would be optimal given knowledge of the population treatment effect in a general setting. The procedure uses multiple hypothesis testing methods to determine a subset of the population for which assignment to treatment can be determined to be optimal after conditioning on all available information, with a prespecified level of confidence. A Monte Carlo study confirms that the inference procedure has good small sample behavior. We apply the method to study Project STAR and the optimal assignment of a small class intervention based on school and teacher characteristics.

The SQUALO project (Star formation in QUiescent And Luminous Objects) I: clump-fed accretion mechanism in high-mass star-forming objects

ABSTRACT The formation mechanism of the most massive stars is far from completely understood. It is still unclear if the formation is core-fed or clump-fed, i.e. if the process is an extension of what happens in low-mass stars, or if the process is more dynamical such as a continuous, multiscale accretion from the gas at parsec (or even larger) scales. In this context, we introduce the SQUALO project, an ALMA 1.3 and 3 mm survey designed to investigate the properties of 13 massive clumps selected at various evolutionary stages, with the common feature that they all show evidence for accretion at the clump scale. In this work, we present the results obtained from the 1.3 mm continuum data. Our observations identify 55 objects with masses in the range 0.4 ≤ M ≤ 309 M⊙, with evidence that the youngest clumps already present some degree of fragmentation. The data show that physical properties such as mass and surface density of the fragments and their parent clumps are tightly correlated. The minimum distance between fragments decreases with evolution, suggesting a dynamical scenario in which massive clumps first fragment under the influence of non-thermal motions driven by the competition between turbulence and gravity. With time gravitational collapse takes over and the fragments organize themselves into more thermally supported objects while continuing to accrete from their parent clump. Finally, one source does not fragment, suggesting that the support of other mechanisms (such as magnetic fields) is crucial only in specific star-forming regions.

Same race teachers do not necessarily raise academic achievement

Numerous studies have found that students who are of the same race as their teacher experience increased academic achievement. In this paper, I attempt to explain when these benefits occur and which students are most likely to achieve the largest gains. Using exogenous variation in student–teacher matches and classroom composition from Tennessee’s Project STAR experiment, I find that below average achieving students benefit most from having a teacher of the same race, but the benefits from matching can be substantially reduced in smaller classes. Moreover, the effect is decreased in racially homogeneous classes where the teacher is the majority race.

Contamination Bias in Linear Regressions

We study the interpretation of regressions with multiple treatments and flexible controls. Such regressions are often used to analyze stratified randomized control trials with multiple intervention arms, to estimate value-added (for, e.g., teachers) with observational data, and to leverage the quasi-random assignment of decision-makers (e.g. bail judges). We show that these regressions generally fail to estimate convex averages of heterogeneous treatment effects, even when the treatments are conditionally randomly assigned and the controls are sufficiently flexible to avoid omitted variables bias. Instead, estimates of each treatment's effects are generally contaminated by a non-convex average of the effects of other treatments. Thus, recent concerns about heterogeneity-induced bias in regressions leveraging potential outcome restrictions (e.g. parallel trends assumptions) also arise with "design-based" identification strategies. We discuss solutions to the contamination bias and propose a new class of efficient estimators of weighted average effects that avoid bias. In a re-analysis of the Project STAR trial, we find minimal bias because treatment effect heterogeneity is largely idiosyncratic. But sizeable contamination bias arises when effect heterogeneity becomes correlated with treatment propensity scores.

PROJECT STAR (Midwestern Prevention Project): Overview.

The program designed to prevent substance use should be planned in multiple dimensions. One of these programs is Project Star. This study aims to evaluate the studies on the Project Star and identify the strengths and weaknesses of the program. For this purpose, the keywords "Project Star" and "Midwestern Prevention Project" were scanned from databases. The results of these studies were evaluated by giving a summary of the studies included in the study. As a result, the strengths of Project Star are that it is multidimensional, focuses on early development periods, includes the individual's ecological environment, and reduces substance use in later development periods, and not having an internet-based version. This situation has been identified as its weaknesses since its situation in other societies is unknown due to its cost and limited international applications.

Innovative professional training approaches on the german national clinical guideline for NSSI in adolescents

IntroductionGerman mental health care providers report to encounter many cases of NSSI in their professional context, but only around 50% know about the treatment guidelines for NSSI of children and adolescents. Many consider professional training about NSSI as necessary for themselves. In response to this need, within the project Star Train different strategies of dissemination of the content of the guidelines were developed.ObjectivesThis study aims at comparing the effectiveness of different strategies of dissemination: printed material, e-learning and blended-learning.Methods Participants were randomly assigned to one of three different learning formats: printed material, e-learning, and blended-learning. Via online-survey participants provide pre- and post-training self-assessments of their knowledge of NSSI, practical skills, self-efficacy in handling cases of NSSI and attitudes towards NSSI and those affected. Additionally a multiple-choice-test of NSSI is assessed. For data-analyses between-group and within-group comparisons were conducted using a mixed design ANOVA. To ensure quality of learning formats, user-satisfaction was surveyed.ResultsData of the pretest-posttest comparison group design show that knowledge, practical skills, and self-efficacy in handling cases of NSSI raise for all participants and that attitudes towards NSSI and those affected are improved. There is no difference between the learning formats, thus all participants profit equally from their education. User satisfaction is high.ConclusionsResults of this study suggest that the developed different training strategies can contribute equally to a better understanding and enhance skills of professionals regarding NSSI. The choice of training method could be driven by considering which goals want to be achieved and cost-value ratio.

Capacity Building in Teaching Mathematics through Problem Solving

Drawing from the national evaluation of the DOST-SEI’s project STAR, this paper presents the case of the Northern Mindanao. Teaching Mathematics through Problem Solving (TMPS), interdisciplinary contextualization, and Lesson Study are the main training content of the project STAR. A good mixture of theory presentation, demonstration, practice, feedbacking and coaching compose the typical training design of the project. This evaluation study revealed that the training from 2014-2017 have applied the training content in different settings, mostly in the classroom and among small group of teachers The participants’ teaching practice are impacted by the training evidenced by the change of their beliefs, attitudes and roles in the classroom Teacher participants also claimed to have gained professional skills as they continue on their implementation but have also encountered various challenges such as the lack of monitoring and feedback. Form the insights on student interviews and class observations, there are evidences that students indeed benefitted from the teachers’ implementation of the training content. Recommendations based from the results are also discussed..

Direct and Indirect Effects under Sample Selection and Outcome Attrition

This paper extends the evaluation of direct and indirect treatment effects, i.e., mediation analysis, to the case that outcomes are only partially observed due to sample selection or outcome attrition. We assume sequential conditional independence of the treatment and the mediator, i.e., the variable through which the indirect effect operates. We also impose missing at random or instrumental variable assumptions on the outcome attrition process. Under these conditions, we derive identification results for the effects of interest that are based on inverse probability weighting by specific treatment, mediator, and/or selection propensity scores. We also provide a simulation study and an empirical application to the U.S. Project STAR data in which we assess the direct impact and indirect effect (via absenteeism) of smaller kindergarten classes on math test scores. The estimators considered are available in the ‘causalweight’ package for the statistical software ‘R’.

Own Motivation, Peer Motivation, and Educational Success

I study how motivation shapes own and peers' educational success. Using data from Project STAR, I find that academic motivation in early elementary school, as measured by a standardized psychological test, predicts contemporaneous and future test scores, high school GPA, and college-test taking over and above cognitive skills. Exploiting random assignment of students to classes, I find that exposure to motivated classmates causally affects contemporaneous reading achievement, a peer effect that operates over and above spillovers from classmates' past achievement and socio-demographic composition. However, peer motivation does not affect longer-term educational success, likely because it does not change own motivation.

Own Motivation, Peer Motivation, and Educational Success

I study how motivation shapes own and peers' educational success. Using data from Project STAR, I find that academic motivation in early elementary school, as measured by a standardized psychological test, predicts contemporaneous and future test scores, high school GPA, and college-test taking over and above cognitive skills. Exploiting random assignment of students to classes, I find that exposure to motivated classmates causally affects contemporaneous reading achievement, a peer effect that operates over and above spillovers from classmates' past achievement and socio-demographic composition. However, peer motivation does not affect longer-term educational success, likely because it does not change own motivation.

Estimating causal effects of class size in secondary education: evidence from TIMSS

ABSTRACT The effectiveness of class size reduction on student performance has been of great research interest and policy debate worldwide. Nevertheless, the evidence has been largely inconclusive partially due to potential bias arising from non-random placement of students and teachers in classrooms of different sizes. This study applied instrumental variable (IV) methods and used a regression discontinuity design (RDD) to conduct analyses of TIMSS data in 2003, 2007 and 2011. The purpose was to investigate over time the effects of class size on eighth grade students’ cognitive and non-cognitive outcomes on five mathematics and science subjects in four European countries (i.e. Hungary, Lithuania, Romania and Slovenia). IV estimates indicate that in Romania in 2003 smaller classes had significant and positive effects on academic scores in mathematics, physics, chemistry and earth science and in 2007 on enjoyment to learn mathematics. In Lithuania, in 2011 small classes had significant and positive effects on enjoyment to learn biology and chemistry and learning chemistry well. In 2007 however, the effects were reversed on some of the biology related non-cognitive outcomes. Overall, the class size effects that were significant were also substantial in magnitude and typically much larger than the effects reported in Project STAR.

Longitudinal Associations Between Sexual Communication With Friends and Sexual Behaviors Through Perceived Sexual Peer Norms

ABSTRACT The role of peers in adolescents’ sexual behaviors is not yet fully understood. We investigated the association between sexual communication with friends (at T1) and subsequent changes in adolescents’ experience with sexual behaviors (between T1–T3), and examined whether this association was explained by adolescents’ perceptions of three sexual peer norms (at T2): (1) peers’ sexual behaviors (descriptive norms), (2) peers’ approval of sexual behaviors (injunctive norms), and (3) peer pressure to have sex. The data source was Project STARS, a longitudinal study on adolescent sexual development in the Netherlands, collected via online self-report questionnaires from 1,116 adolescents (11.5–17.9 years). Adolescents who communicated more frequently with their friends about sexuality-related topics at T1 reported significantly larger increases in their experience with different sexual behaviors between T1–T3. More sexual communication with friends also predicted adolescents subsequently perceiving more 1) peer sexual behaviors, 2) peer approval of sex, and 3) peer pressure to have sex. These stronger perceptions, in turn, predicted larger increases in their sexual behaviors between T1–T3. After adjusting for the three norms simultaneously, the main association between sexual communication with friends and sexual behavior change weakened but remained significant. Inspection of specific indirect effects showed this link was explained by injunctive norms only. No gender differences were found.

Support and Tracking to Achieve Results (Project STAR)

Support and Tracking to Achieve Results (Project STAR)

The Long-Term Impacts of Low-Achieving Childhood Peers: Evidence from Project STAR

AbstractThis paper evaluates how sharing a kindergarten classroom with low-achieving repeaters affects the long-term educational performance of regular first-time kindergarten students. Exploiting random assignment of teachers and students to classes in Project STAR, I document three sets of causal impacts: students who are exposed to repeaters (1) score lower on a standardized math test at the end of kindergarten, an effect that fades out in later grades; (2) show persistent improvements in noncognitive skills such as effort and discipline; and (3) are more likely to graduate from high school and to take a college entrance exam around the age of 18. I argue that the positive spillovers on long-term educational attainment are driven by the differential accumulation of noncognitive skills by repeater-exposed students during childhood. Results are consistent with the hypothesis that the improvements in these skills are driven by behavioral adjustments of teachers to the presence of repeaters in the classroom.

Project Star Catcher

Modern immersive virtual reality experiences have the unique potential to motivate patients undergoing physical therapy for performing intensive repetitive task-based treatment and can be utilized to collect real-time user data to track adherence and compliance rates. This article reports the design and evaluation of an immersive virtual reality game using the HTC Vive for upper limb rehabilitation, titled “Project Star Catcher” (PSC), aimed at users with hemiparesis. The game mechanics were adapted from modified Constraint Induced Therapy (mCIT), an established therapy method where users are asked to use the weaker arm by physically binding the stronger arm. Our adaptation changes the physical to psychological binding by providing various types of immersive stimulation to influence the use of the weaker arm. PSC was evaluated by users with combined developmental and physical impairments as well as stroke survivors. The results suggest that we were successful in providing a motivating experience for performing mCIT as well as a cost-effective solution for real-time data capture during therapy. We conclude the article with a set of considerations for immersive virtual reality therapy game design.

Long-term consequences in lung and bone associated with hospital-acquired severe acute respiratory syndrome: a 15-year follow-up from a prospective cohort study

BackgroundSevere acute respiratory syndrome (SARS) broke out in China and spread to all over the world in 2003. Without comprehensive protection, during a severe hospital outbreak in the Peking University People's Hospital (PKUPH), there were 78 patients diagnosed with SARS and two deaths. During treatment, most patients received large doses of steroid shock therapy, which may result in complications of femoral head necrosis and pulmonary fibrosis. We aimed to follow up the condition of lung and bone in those patients. MethodsWe did an observational cohort study of patients with SARS from 2003 to 2018. We carried out pulmonary CT scans, hip joint MRI tests, pulmonary function tests, and hip joint functional assessment to evaluate the recovery condition of lung damage and femoral head necrosis according to patients' willingness. We used linear regression, and mixed-model repeated-measures analysis to measure the change of lung interstitial and femoral head necrosis volume. This study was authorised by the Ethics Committee of Peking University People's Hospital (2018PHB010-01). All recruited SARS patients signed informed consent for the study. This study is registered with ClinicalTrials.gov, number NCT03443102. FindingsThere were 80 medical staff patients with SARS altogether in Peking University People's Hospital. Two patients died of SARS in 2003 and 78 patients were enrolled in this study from August, 2003, to March, 2018. 71 patients completed the 15 years' follow-up and seven patients were missing. Pulmonary injury scope on lung CT improved from 2003 (9·40%, SD 7·83) to 2004 (3·20%, 4·78; p≤0·001), and thereafter remained steady to 2018 (4·60%, 6·37). Pulmonary function items in patients with SARS did not differ between 2006 and 2018. The recovery extent of pulmonary function items between 2006 and 2018 in patients with lung interstitial change (n=13), was less than that without lung interstitial changes (n=23), especially in one-second ratio (FEV1/FVC, t=2·21, p=0·04) and mid-flow of maximum expiration (FEF25–75%, t=2·76, p=0·01). The volume of femoral head necrosis decreased significantly from 2003 (38·83%, SD 21·01) to 2005 (30·38%, 20·23; p=0·0002), then decreased slowly from 2005 to 2013 (28·99%, 20·59) and thereafter remained steady to 2018 (25·52%, 15·51)%. InterpretationDamaged lung interstitial and functional decline induced by SARS mainly recovered in the next 1–2 years after rehabilitation. The natural process of femoral head necrosis caused by large doses of steroid shock therapy in SARS patients was not progressive, while partially reversible. FundingChinese National Ministry of Science and Technology 973 Project (number 2014CB542201), Beijing science and technology new star cross subject (2018019), Fund for Fostering Young Scholars of Peking University Health Science Center (BMU2017PY013), National Natural Science Foundation (numbers 31771322,31571235, 31571236, 31271284).

Does a Successful Randomized Experiment Lead to Successful Policy? Project Challenge and What Happened in Tennessee After Project STAR

A growing number of policy makers request research evidence before making policy decisions. Yet the evidence, when provided, may have little impact on policy. In this article, we revisit how Tennessee handled class size policy in 1984-93. The conventional history is an inspiring narrative of evidence-based policy. The state funded a randomized experiment (Project STAR), which showed that reducing class sizes to 15 could raise test scores. It then funded class size reduction in the poorest school districts (Project Challenge), achieving similar effects. Finally, the state reduced class sizes statewide (under the Basic Education Program). Our revised history paints a less inspiring picture. Though Project STAR was exemplary, Project Challenge was not. Evidence from district report cards suggest that the districts targeted by Project Challenge did not reduce class sizes and did not raise test scores. After Project Challenge, Tennessee’s Basic Education Program did reduce class sizes statewide, but the reduction was token, taking average student-teacher ratios from 26 down to 25. Later other states reduced class sizes, citing evidence from Project STAR, but the reductions and contexts differed from those in Project STAR, and effects were disappointing. If evidence is to improve social outcomes, it must be better integrated into policy decisions.

Randomized controlled trials informing public policy: Lessons from project STAR and class size reduction

Randomized controlled trials (RCTs) and related research strategies are increasingly seen as the preferred methodology for evaluating policy interventions, but a single-minded focus on identifying causal effects limits their capacity to support actual policy decisions. A detailed look at Project STAR illustrates this point and offers some possible correctives. Initiated by the Tennessee legislature to help decide whether to enact state-wide class size reduction (CSR), STAR compared the test scores of students randomly assigned to classes of different size. It addressed a well-formed research question, but focused narrowly on refining a single link in a long chain of evidence necessary to address the policy question at hand: whether CSR would be a good use of a large increase in education spending. It disregarded the limitations of test scores as indicators of education quality and ignored general equilibrium effects on teacher quality and salaries. Moreover, the emphasis it placed on estimating average CSR effects in a given setting diverted attention from the heterogeneity of these effects and the conditions that mediated their impact, limiting its external validity. These observations continue to be relevant for the design of policy-oriented research, and for the academic training of empirical economists.