Page 466 - Encyclopedia of Nursing Research

QuASI-ExPERIMENTAl RESEARcH n 433

other, and it is often useful to minimize con- point in time. When the researcher studies
tact between treatment and control groups. one group of subjects, the subjects act as their
In time series designs, the researcher own controls, which provides the researcher Q
does not always use a control group and with equivalent control groups. Time series
does not use randomization. An interrupted designs are used when a control group pop-
time series study uses several observations ulation is not available. When only one group
of subjects over time with a treatment given is available to the researcher, the time series
at a specified point (or longitudinally over design significantly increases the strength of
time, with start and end time points). A time the research.
series study can be designed to study the
same individuals at specified intervals or to Ivo Abraham
study different individuals at some common Karen MacDonald