Measurement variability of radiologists when measuring brain tumors.

Background: In oncology trials, response evaluation criteria are pivotal in developing new treatments. This study examines the influence of measurement variability in brain lesions on response classification, considering long-standing cut-offs for progression and response were determined before the era of submillimeter resolutions of medical imaging.

Methods: We replicate a key study using modern radiological tools.

An evaluation of mindful clinical congruence in medical students after course-based teaching.

Purpose: We questioned whether an intensive experiential core course would change medical students' intention to practice mindful clinical congruence. Our primary hypothesis was that we would see more of a change in the intention to practice mindful clinical congruence in those who had taken versus not yet taken our course.

Methods: From a class of 179 in second year we recruited 57 (32%) students who had been already divided into three groups that completed the course in successive periods.

Deaths averted: An unbiased alternative to rate ratios for measuring the performance of cancer screening programs.

Introduction: Screening trials and meta-analyses emphasize the ratio of cancer death rates in screening and control arms. However, this measure is diluted by the inclusion of deaths from cancers that only became detectable after the end of active screening.

Methods: We review traditional analysis of cancer screening trials and show that ratio estimates are inevitably biased to the null, because follow-up (FU) must continue beyond the end of the screening period and thus includes cases only becoming detectable after screening ends.

Ranking versus rating in peer review of research grant applications.

The allocation of public funds for research has been predominantly based on peer review where reviewers are asked to rate an application on some form of ordinal scale from poor to excellent. Poor reliability and bias of peer review rating has led funding agencies to experiment with different approaches to assess applications. In this study, we compared the reliability and potential sources of bias associated with application rating with those of application ranking in 3,156 applications to the Canadian Institutes of Health Research.

The (Im)precision of Life Expectancy Numbers.

Life expectancy figures for countries and population segments are increasingly being reported to more decimal places and used as indicators of the strengths or failings of countries' health and social systems. Reports seldom quantify their intrinsic statistical imprecision or the age-specific numbers of deaths that determine them. The SE formulas available to compute imprecision are all model based.

"Translating" All-Cause Mortality Rate Ratios or Hazard Ratios to Age-, Longevity-, and Probability-Based Measures.

Epidemiologists commonly use an adjusted hazard ratio or incidence density ratio, or a standardized mortality ratio, to measure a difference in all-cause mortality rates. They seldom translate it into an age-, time-, or probability-based measure that would be easier to communicate and to relate to. Several articles have shown how to translate from a standardized mortality ratio or hazard ratio to a longevity difference, a difference in actuarial ages, or a probability of being outlived.

LASSO type penalized spline regression for binary data.

Background: Generalized linear mixed models (GLMMs), typically used for analyzing correlated data, can also be used for smoothing by considering the knot coefficients from a regression spline as random effects. The resulting models are called semiparametric mixed models (SPMMs). Allowing the random knot coefficients to follow a normal distribution with mean zero and a constant variance is equivalent to using a penalized spline with a ridge regression type penalty.

Cattle and sheep farmers' opinions on the provision and use of abattoir rejection data in the United Kingdom.

Background: Communication between farmers and veterinary surgeons is reported to differ when involving abattoir rejection data on cattle or sheep.

Methods: Using surveys, distributed online and on paper at livestock markets, this study describes the interest and positive opinion of a sample of UK cattle and sheep farmers in receiving abattoir data.

Results: Forty-nine per cent of respondents always received abattoir data (n=37/76).

Modeling perinatal mortality in twins via generalized additive mixed models: a comparison of estimation approaches.

Background: The analysis of twin data presents a unique challenge. Second-born twins on average weigh less than first-born twins and have an elevated risk of perinatal mortality. It is not clear whether the risk difference depends on birth order or their relative birth weight.

Effect of an Electronic Medication Reconciliation Intervention on Adverse Drug Events: A Cluster Randomized Trial.

Importance: Adverse drug events (ADEs) account for up to 16% of emergency department (ED) visits and 7% of hospital admissions. Medication reconciliation is required for hospital accreditation because it can reduce medication discrepancies, but there is no evidence that reducing discrepancies reduces ADEs or other adverse outcomes.

Objective: To evaluate whether electronic medication reconciliation reduces ADEs, medication discrepancies, and other adverse outcomes compared with usual care.

A more intuitive and modern way to compute a small-sample confidence interval for the mean of a Poisson distribution.

Small-sample confidence intervals for the mean of a Poisson distribution have been used since the 1930s. They can be computed by trial and error, or using a computation-saving link that few are aware of and that, even if they are, is neither intuitive nor easy to remember. I trace how and why this link has been used, even if the basis for it has been lost or ignored.

A comparison of technique survival in Canadian peritoneal dialysis and home hemodialysis patients.

Background: High discontinuation rates remain a challenge for home hemodialysis (HHD) and peritoneal dialysis (PD). We compared technique failure risks among Canadian patients receiving HHD and PD.

Methods: Using the Canadian Organ Replacement Register, we studied adult patients who initiated HHD or PD within 1 year of beginning dialysis between 2000 and 2012, with follow-up until 31 December 2013.

Ability to Predict New-Onset Psychological Distress Using Routinely Collected Health Data: A Population-Based Cohort Study of Women Diagnosed With Breast Cancer.

The primary objective of this study was to identify the predictors of new-onset psychological distress available in routinely collected administrative health databases for women diagnosed with breast cancer. The secondary objective was to explore whether the predictors vary based on the period of cancer care. A population-based cohort study followed 16,495 female patients with newly diagnosed breast cancer who did not experience psychological distress during the 14 months before breast cancer surgery.

Individually-matched etiologic studies: classical estimators made new again.

With greater access to regression-based methods for confounder control, the etiologic study with individual matching, analyzed by classical (calculator) methods, lost favor in recent decades. This design was costly, and the data sometimes mis-analyzed. Now, with Big Data, individual matching becomes an economical option.

Assessment of potential bias in research grant peer review in Canada.

Background: Peer review is used to determine what research is funded and published, yet little is known about its effectiveness, and it is suspected that there may be biases. We investigated the variability of peer review and factors influencing ratings of grant applications.

Methods: We evaluated all grant applications submitted to the Canadian Institutes of Health Research between 2012 and 2014.

Statistical Behaviors: Personal and Computer-Aided Observations.

My early years as a statistician were with the Eastern Co-operative Oncology Group and the Radiation Oncology Therapy Group; three of these years were spent at the Sidney Farber Cancer Institute. Later, I collaborated widely with investigators in many clinical research areas. I reflect on the "statistical interrogations of nature" I saw (and helped some of these) investigators plan and carry out.

Mortality reductions due to mammography screening: Contemporary population-based data.

Our objective was to compare breast cancer mortality in two regions of the Republic of Ireland that introduced a screening programme eight years apart, and to estimate the steady-state mortality deficits the programme will produce. We carried out age- and year-matched between-region comparison of breast cancer mortality rates, and of incidence rates of stage 2-4 breast cancer, in the eligible cohorts. The regions comprised counties that, beginning in early 2000 (region 1) and late 2007 (region 2), invited women aged 50-64 to biennial mammography screening.

Disaggregating the mortality reductions due to cancer screening: model-based estimates from population-based data.

The mortality impact in cancer screening trials and population programs is usually expressed as a single hazard ratio or percentage reduction. This measure ignores the number/spacing of rounds of screening, and the location in follow-up time of the averted deaths vis-a-vis the first and last screens. If screening works as intended, hazard ratios are a strong function of the two Lexis time-dimensions.

Development and validation of a new pediatric resuscitation and trauma outcome (PRESTO) model using the U.S. National Trauma Data Bank.

Background: There is a need for a pediatric trauma outcomes benchmarking model that is adapted for Low-and-Middle-Income Countries (LMICs). We used the National-Trauma-Data-Bank (NTDB) and applied constraints specific to resource-poor environments to develop and validate an LMIC-specific pediatric trauma score.

Methods: We selected a sample of pediatric trauma patients aged 0-14years in the NTDB from 2007 to 2012.

Sample Size Estimation for Random-effects Models: Balancing Precision and Feasibility in Panel Studies.

Panel study designs are common in environmental epidemiology, whereby repeated measurements are collected from a panel of subjects to evaluate short-term within-subject changes in response variables over time. In planning such studies, questions of how many subjects to include and how many different exposure conditions to measure are commonly asked at the design stage. In practice, these choices are constrained by budget, logistics, and participant burden and must be carefully balanced against statistical considerations of precision and power.

Predictors of distress in female breast cancer survivors: a systematic review.

Purpose: Unmanaged distress has been shown to adversely affect survival and quality of life in breast cancer survivors. Fortunately, distress can be managed and even prevented with appropriate evidence-based interventions. Therefore, the objective of this systematic review was to synthesize the published literature around predictors of distress in female breast cancer survivors to help guide targeted intervention to prevent distress.