What is the interruption in an interrupted time series design?
The interruption in the time series refers to the specific point at which the intervention was implemented. In addition, the time series design controls for confounding effects that may be time-dependent (eg, seasonality) [1–3].
What is the difference between time series design and interrupted time series design?
The time series refers to the data over the period, while the interruption is the intervention, which is a controlled external influence or set of influences. Effects of the intervention are evaluated by changes in the level and slope of the time series and statistical significance of the intervention parameters.
What is the most important threat to validity in time series designs Why is it the most important?
The most common threat to validity is history—the possibility that some other event caused the observed effect in the time series. Although history limits the ability to draw causal inferences from single ITSA models, it can be controlled for by using a comparable control group to serve as the counterfactual.
What is single group interrupted time series design?
INTRODUCTION Single-group interrupted time-series analysis (ITSA) is a popular evaluation strategy for observational data in which a single unit is studied (e.g., an individual, a city, or a country), the dependent variable is a serially ordered time series, and multiple observations are captured in both the pre- and …
When would you use an interrupted time series design?
2 The interrupted time series (ITS) study design is increasingly being used for the evaluation of public health interventions; it is particularly suited to interventions introduced at a population level over a clearly defined time period and that target population-level health outcomes.
What is an interrupted time series design example?
In an interrupted time series-design, a time series like this one is “interrupted” by a treatment. In one classic example, the treatment was the reduction of the work shifts in a factory from 10 hours to 8 hours (Cook & Campbell, 1979).
Is a time series design quasi-experimental?
A type of quasi-experimental design where a series of periodic measurements is taken from one group of test units, followed by a treatment, then another series of measurements.
What are the two general categories of quasi-experimental designs?
Quasi-experimental research involves the manipulation of an independent variable without the random assignment of participants to conditions or orders of conditions. Among the important types are nonequivalent groups designs, pretest-posttest, and interrupted time-series designs.
What limitation does a quasi-experiment create?
The lack of random assignment is the major weakness of the quasi-experimental study design. Associations identified in quasi-experiments meet one important requirement of causality since the intervention precedes the measurement of the outcome.