Using nonequivalent dependent variables to reduce internal validity threats in quasi‐experiments: Rationale, history, and examples from practice

Coryn, Chris L. S.; Hobson, Kristin A.

doi:10.1002/ev.375

Cited by 38 publications

(27 citation statements)

References 18 publications

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“…This is a problem common to studies examining policy interventions which are implemented simultaneously across a population [35]. A partial solution to this problem is to include non-equivalent dependent variables [35], [46], [47]–variables not expected to respond to the intervention, but exposed to the same historical validity threats [45]. In this study we used two non-equivalent variables to control for confounding factors, these were: robbery, and total crime.…”

Section: Methodsmentioning

confidence: 99%

Evaluating the Impact of Flexible Alcohol Trading Hours on Violence: An Interrupted Time Series Analysis

2013

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BackgroundOn November 24th 2005, the Government of England and Wales removed regulatory restrictions on the times at which licensed premises could sell alcohol. This study tests availability theory by treating the implementation of Licensing Act (2003) as a natural experiment in alcohol policy.MethodsAn interrupted time series design was employed to estimate the Act’s immediate and delayed impact on violence in the City of Manchester (Population 464,200). We collected police recorded rates of violence, robbery, and total crime between the 1st of February 2004 and the 31st of December 2007. Events were aggregated by week, yielding a total of 204 observations (95 pre-, and 109 post-intervention). Secondary analysis examined changes in daily patterns of violence. Pre- and post-intervention events were separated into four three-hour segments 18∶00–20∶59, 21∶00–23.59, 00∶00–02∶59, 03∶00–05∶59.ResultsAnalysis found no evidence that the Licensing Act (2003) affected the overall volume of violence. However, analyses of night-time violence found a gradual and permanent shift of weekend violence into later parts of the night. The results estimated an initial increase of 27.5% between 03∶00 to 06∶00 (ω = 0.2433, 95% CI = 0.06, 0.42), which increased to 36% by the end of the study period (δ = −0.897, 95% CI = −1.02, −0.77).ConclusionsThis study found no evidence that a national policy increasing the physical availability of alcohol affected the overall volume of violence. There was, however, evidence suggesting that the policy may be associated with changes to patterns of violence in the early morning (3 a.m. to 6 a.m.).

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Section: Methodsmentioning

confidence: 99%

Evaluating the Impact of Flexible Alcohol Trading Hours on Violence: An Interrupted Time Series Analysis

2013

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“…Secondly, given the limited research that was available, we chose to include both controlled and single group designs. Quasi-experimental designs pose a greater threat to internal validity (Coryn, & Hobson, 2011). Consequently, the results of the studies used in this review may have been confounded and with them perhaps our conclusions.…”

Section: Study Limitationsmentioning

confidence: 97%

A systematic review of the effect of physical exercise on cognition in stroke and traumatic brain injury patients

Vanderbeken

Kerckhofs

2017

NRE

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Abstract. OBJECTIVE:To determine whether physical exercise enhances cognition following TBI or stroke. DATA SOURCES: Studies were identified through searches of PubMed, ScienceDirect and the reference lists of papers that were included for full-text evaluation. Medical subject headings from three concepts, i.e. brain injury, physical exercise and cognition, were used to incorporate related search terms. STUDY SELECTION: Included were all trials published in English that assessed cognition before and after an exercise intervention in human adults with TBI or stroke. Nine randomized and two non-randomized controlled trials, as well as three single group pre-post studies were included. DATA EXTRACTION: Relevant data concerning the methods and results of the included studies were extracted. Methodological quality of the RCT's was evaluated using the PEDro scale. Non-randomized trials were assessed using the Downs and Black checklist. DATA SYNTHESIS: The included trials were generally of medium methodological quality, though often plagued with issues of internal and external validity. The studies exhibited great heterogeneity, rendering a meta-analysis infeasible. CONCLUSIONS: Though well-designed studies are still needed, the preponderance of evidence suggests a positive effect of physical exercise on global cognitive functioning, especially in the chronic stages of a brain injury. Time after injury as well as the duration of the exercise program are mediating factors.

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“…Use of such nonequivalent dependent variables (NEDV) is a technique used in quasi-experimental designs to mitigate internal threats to validity in quasi-experimental designs. (25) We chose three NEDV's:…”

Section: Nonequivalent Dependent Variablesmentioning

confidence: 99%

Pathways Project: Development of a Multimodal Innovation To Improve Kidney Supportive Care in Dialysis Centers

et al. 2021

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Current care models for older patients with kidney failure in the U.S. do not incorporate supportive care approaches. The absence of supportive care contributes to poor symptom management and unwanted forms of care at the end-of-life. Using an Institute for Healthcare Improvement Collaborative Model for Achieving Breakthrough Improvement, we conducted a focused literature review, interviewed implementation experts, and convened a technical expert panel to distill existing evidence into an evidence-based supportive care change package. The change package consists of 14 best practice recommendations for the care of seriously ill patients with kidney failure, emphasizing three key practices: systematic identification of seriously ill patients, goals of care conversations with identified patients, and care options to respond to patient wishes. Implementation will be supported through a collaborative consisting of three intensive learning sessions, monthly learning and collaboration calls, site data feedback, and quality improvement technical assistance. To evaluate the change package's implementation and effectiveness, we designed a mixed methods hybrid study. 1) Effectiveness evaluation (including patient outcomes and staff perception of the effectiveness of the implementation of the change package), 2) Quality improvement monitoring via monthly tracking of a suite of quality improvement indicators tied to the change package; and 3) Implementation evaluation conducted by the external evaluator using mixed methods to assess implementation of the Collaborative processes. Ten dialysis centers across the country treating approximately 1,550 patients will participate. This article describes the process informing the intervention design, components of the intervention, evaluation design and measurements, and preliminary feasibility assessments.

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Using nonequivalent dependent variables to reduce internal validity threats in quasi‐experiments: Rationale, history, and examples from practice

Cited by 38 publications

References 18 publications

Evaluating the Impact of Flexible Alcohol Trading Hours on Violence: An Interrupted Time Series Analysis

Evaluating the Impact of Flexible Alcohol Trading Hours on Violence: An Interrupted Time Series Analysis

A systematic review of the effect of physical exercise on cognition in stroke and traumatic brain injury patients

Pathways Project: Development of a Multimodal Innovation To Improve Kidney Supportive Care in Dialysis Centers

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