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1Tassos Sarampalis
Chapters 8 and 9
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• Non-equivalent groups and historical controls
• Interrupted time series
• Single-case experimental designs
• Cross-lagged correlational designs
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• Similar to real experiments
• Typically involve pre- and post-treatment measurements
• But:
Without random assignment -> Groups are not equivalent
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also known as literature controls
• Easier
• Fewer ethical worries
But:
Caution because of selection and report bias
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97 100 103 106 109
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107 110 113 116 119 1220
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118 120 122 124 126
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97 100 103 106 109
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107 110 113 116 119 122
0
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118 120 122 124 126
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95 100 105 110 115 120 125 130
Lived Died Total % who lived
Hospital A 790 210 1000
Hospital B 900 100 1000
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Lived Died Total % who lived
Hospital A 790 210 1000 79%
Hospital B 900 100 1000 90%
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Lived Died Total % who lived
Hospital A 790 210 1000 79%
Hospital B 900 100 1000 90%
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Lived Died Total % who lived
Hospital A 580 10 590
Hospital B 860 30 890
Lived Died Total % who lived
Hospital A 210 200 410
Hospital B 40 70 110
Fair Condition and Better
Poor Condition and Worse
Lived Died Total % who lived
Hospital A 790 210 1000 79%
Hospital B 900 100 1000 90%
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Lived Died Total % who lived
Hospital A 580 10 590 98.3%
Hospital B 860 30 890 96.6%
Lived Died Total % who lived
Hospital A 210 200 410 51.2%
Hospital B 40 70 110 36.3%
Fair Condition and Better
Poor Condition and Worse
• A series of discreet measurements
• A clear definition of the beginning and ending of the treatment
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• Regular
• Seasonal
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N
N+
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0 Time lag
Au
toco
rrela
tio
n C
oe
ff.
• Repeated observations, but on a single case (or small number of cases)
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A1 A2
B1 B2
time
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A1 A2
B1 B2
time
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A1 A2
B1 B2
time
Test-Retest Correlations
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A1 A2
B1 B2
time
Test-Retest Correlations
Synchronous Correlations
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A1 A2
B1 B2
time
Test-Retest Correlations
Synchronous Correlations
Cross-Lagged Correlations
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A1 A2
B1 B2
time
Test-Retest Correlations
Synchronous Correlations
Cross-Lagged Correlations
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Simple = from the undivided population
Random = every sampling unit is equally likely to be selected
With Replacement
Without Replacement
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Stratified = First divide population into strata
Random = In each stratum, each unit is equally likely to be selected
Advantage:
Reduced sampling error (improved accuracy)
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