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. Author manuscript; available in PMC: 2017 Oct 1.
Published in final edited form as: Infect Control Hosp Epidemiol. 2016 Jun 7;37(10):1135–1140. doi: 10.1017/ice.2016.117

Table 2.

Major Quasi-experimental design types and subtypes

Type and Subtype Description Notation
A. INTERRUPTED TIME-SERIES QUASI-EXPERIMENTAL DESIGNS
#15 Interrupted time series that uses switching replications and a control group A1c A2c A3c X A4t A5t A6t removeX A7c A8c A9c A10c
B1c B2c B3c B4c B5c B6c X B7t B8t B9t B10t
#14 Interrupted time series with repeated treatment design13 A1c A2c A3c X A4t A5t removeX A6c A7c X A8t A9t
#13 Interrupted time series removing the treatment at a known time A1c A2c A3c A4c X A5t A6t A7t A8t removeX A9c A10c
#12 Interrupted time series with a nonequivalent dependent variable14 (A1cv, A1cn) (A2cv, A2cn) (A3cv, A3cn) X (A4tv, A4tn) (A5tv, A5tn)
#11 Interrupted time series with an untreated control group12 A1c A2c A3c A4c A5c X A6t A7t A8t A9t A10t
B1c B2c B3c B4c B5c B6c B7c B8c B9c B10c
#10 Simple interrupted time series11, 15 A1c A2c A3c A4c A5c X A6t A7t A8t A9t A10t
B. QUASI-EXPERIMENTAL DESIGNS THAT USE CONTROL GROUPS
# 9 The control group design that uses dependent pretest and posttest samples and switching replications A1c X A2t removeX A3c
B1c B2c X B3t
# 8 The untreated-control group design that uses dependent pretest and posttest samples and a double pretest A1c A2c X A3t
B1c B2c B3c
# 7 The untreated-control group design that uses dependent pretest and posttest samples A1c X A2t
B1c B2c
# 6 The posttest-only design that uses an untreated control group X A1t
B1c
C. QUASI-EXPERIMENTAL DESIGNS THAT DO NOT USE CONTROL GROUPS
# 5 The repeated-treatment design A1c X A2t removeX A3c X A4t
# 4 The removed-treatment design A1c X A2t A3t removeX A4c
# 3 The 1-group pretest-posttest design that uses a nonequivalent dependent variable (A1cv, A1cn) X (A2tv, A2tn)
# 2 The 1-group pretest-posttest design that uses a double pretest A1c A2c X A3t
# 1 The 1-group pretest-posttest design A1c X A2t

Note: Classification types adapted prior publications1, 2; A, B = Groups; 1,2,3, etc.= observations for a Group; X= intervention; removeX = remove intervention; v=variable of interest; n=non-equivalent dependent variable; t=treatment group; c=control group. Time moves from left to right. Citations are published examples from the literature.