The relationship between locus of control and pre-competitive anxiety in highly trained soccer players

Statistical guidelines and expert statements are now available to assist in the analysis and reporting of studies in some biomedical disciplines. We present here a more progressive resource for sample-based studies, meta-analyses, and case studies in sports medicine and exercise science. We offer forthright advice on the following controversial or novel issues: using precision of estimation for inferences about population effects in preference to null-hypothesis testing, which is inadequate for assessing clinical or practical importance; justifying sample size via acceptable precision or confidence for clinical decisions rather than via adequate power for statistical significance; showing SD rather than SEM, to better communicate the magnitude of differences in means and nonuniformity of error; avoiding purely nonparametric analyses, which cannot provide inferences about magnitude and are unnecessary; using regression statistics in validity studies, in preference to the impractical and biased limits of agreement; making greater use of qualitative methods to enrich sample-based quantitative projects; and seeking ethics approval for public access to the depersonalized raw data of a study, to address the need for more scrutiny of research and better meta-analyses. Advice on less contentious issues includes the following: using covariates in linear models to adjust for confounders, to account for individual differences, and to identify potential mechanisms of an effect; using log transformation to deal with nonuniformity of effects and error; identifying and deleting outliers; presenting descriptive, effect, and inferential statistics in appropriate formats; and contending with bias arising from problems with sampling, assignment, blinding, measurement error, and researchers' prejudices. This article should advance the field by stimulating debate, promoting innovative approaches, and serving as a useful checklist for authors, reviewers, and editors.

Neonatal abstinence syndrome (NAS) is a postnatal drug withdrawal syndrome primarily caused by maternal opiate use. No national estimates are available for the incidence of maternal opiate use at the time of delivery or NAS. To determine the national incidence of NAS and antepartum maternal opiate use and to characterize trends in national health care expenditures associated with NAS between 2000 and 2009. A retrospective, serial, cross-sectional analysis of a nationally representative sample of newborns with NAS. The Kids' Inpatient Database (KID) was used to identify newborns with NAS by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code. The Nationwide Inpatient Sample (NIS) was used to identify mothers using diagnosis related groups for vaginal and cesarean deliveries. Clinical conditions were identified using ICD-9-CM diagnosis codes. NAS and maternal opiate use were described as an annual frequency per 1000 hospital births. Missing hospital charges (<5% of cases) were estimated using multiple imputation. Trends in health care utilization outcomes over time were evaluated using variance-weighted regression. All hospital charges were adjusted for inflation to 2009 US dollars. Incidence of NAS and maternal opiate use, and related hospital charges. The separate years (2000, 2003, 2006, and 2009) of national discharge data included 2920 to 9674 unweighted discharges with NAS and 987 to 4563 unweighted discharges for mothers diagnosed with antepartum opiate use, within data sets including 784,191 to 1.1 million discharges for children (KID) and 816,554 to 879,910 discharges for all ages of delivering mothers (NIS). Between 2000 and 2009, the incidence of NAS among newborns increased from 1.20 (95% CI, 1.04-1.37) to 3.39 (95% CI, 3.12-3.67) per 1000 hospital births per year (P for trend < .001). Antepartum maternal opiate use also increased from 1.19 (95% CI, 1.01-1.35) to 5.63 (95% CI, 4.40-6.71) per 1000 hospital births per year (P for trend < .001). In 2009, newborns with NAS were more likely than all other hospital births to have low birthweight (19.1%; SE, 0.5%; vs 7.0%; SE, 0.2%), have respiratory complications (30.9%; SE, 0.7%; vs 8.9%; SE, 0.1%), and be covered by Medicaid (78.1%; SE, 0.8%; vs 45.5%; SE, 0.7%; all P < .001). Mean hospital charges for discharges with NAS increased from $39,400 (95% CI, $33,400-$45,400) in 2000 to $53,400 (95% CI, $49,000-$57,700) in 2009 (P for trend < .001). By 2009, 77.6% of charges for NAS were attributed to state Medicaid programs. Between 2000 and 2009, a substantial increase in the incidence of NAS and maternal opiate use in the United States was observed, as well as hospital charges related to NAS.