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Using SAS Choose Design ANOVA Compare Means Regression Examples
Choose Your Switchback Treatment Design

What is a Switchback design?

   What is?
   Single Factor
   Nested
   Factorial
   Split-Plot
   Strip-Plot
   Split-Split
   Repeated Measures

You have chosen your experimental design. On this page you will choose your treatment design by being led through a series of questions.

Identifying your treatment design is affected by the number of treatment factors, how those treatment factors are combined, and what experimental units are associated with each of the treatment factors. The questions below address these three determinants.

If this "sounds like Greek" to you, some background reading is strongly recommended. E.g. see Glossary or do some reading from these resources.

You can see illustrations of the treatment designs in the gray table in the ANOVA tab.

 

Treatment Design Selection Key

1. Do you have more than one treatment factor?

           Yes >>   Go to red arrow 2 below.
           No  >>  You have a Switchback Single Factor design  (example)                                     (What is Single Factor?)

2. Are all levels of one factor combined with all levels of the other factor(s)
          to form the treatment combinations in the experiment?

           Yes >>  Go to red arrow 3 below.
           No  >>  You have a Switchback Nested design                                                               (What is Nested?)

3. Are the treatment factors applied to different types of experimental
          units (e.g. sub-plot or whole plot)?

           Yes: you have some kind of "split-plot" >>  Go to red arrow 4 below.
           No  >>  You have a Switchback Factorial design                                                           (What is Factorial?)

4. Are the large experimental units physically divided into smaller
          experimental units (2 types of experimental units only)?

           Yes >> You have a Switchback Split-Plot design                                                         (What is Split-Plot?)
           No >>  Go to red arrow 5 below.

5. Do you have 2 types of experimental units as in question 4, but the smaller
          experimental units are created by taking measurements over time or space
         (so no physical divisions, and the levels can not be randomized, eg. time 1
          must always come first)?

           Yes >>  You have a Switchback Repeated Measures design                             (What is Repeated Measures?)
           No >>   Go to red arrow 6 below.

6. Are the smaller experimental units in question 4 physically divided again
          to create another type of experimental unit (3 types of experimental units)?

           Yes >>  You have a Switchback Split-Split-Plot design                                           (What is Split-Split-Plot?)
           No >>   Go to red arrow 7 below.


7. The only choice remaining: you must have treatment factors that are both
          applied to large experimental units, which are physically perpendicular to
          each other to create all the treatment combinations.

           Yes >>  You have a Switchback Strip-Plot design                                                        (What is Strip-Plot?)


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