Dear Andrew, 

Thank you for an excellent tool. I am just wetting my feet with it and have come into an unexpected problem. 

NBS does not seem to be recognising my exchange blocks file, or the typed exchange block input: 
[1
2
3
4
5
6
2
4
7
5
4
8
7
5]

Any idea what I'm doing wrong here?

Also, while I have your attention, would you mind me asking you if the two following designs are equivalent (difference in first column/2 columns):
design1:
0 0 1 0 0 0 0 0 0 0
0 0 0 1 0 0 0 0 0 0
0 0 0 0 1 0 0 0 0 0
0 0 0 0 0 1 0 0 0 0
0 0 0 0 0 0 1 0 0 0
0 0 0 0 0 0 0 1 0 0
1 0 0 1 0 0 0 0 0 0
1 0 0 0 0 1 0 0 0 0
1 0 0 0 0 0 0 0 1 0
1 0 0 0 0 0 1 0 0 0
0 1 0 0 0 1 0 0 0 0
0 1 0 0 0 0 0 0 0 1
0 1 0 0 0 0 0 0 1 0
0 1 0 0 0 0 1 0 0 0

contrast1:
[-1 1 0 0 0 0 0 0 0 0]

design2:
0 1 0 0 0 0 0 0 0
0 0 1 0 0 0 0 0 0
0 0 0 1 0 0 0 0 0
0 0 0 0 1 0 0 0 0
0 0 0 0 0 1 0 0 0
0 0 0 0 0 0 1 0 0
-1 0 1 0 0 0 0 0 0
-1 0 0 0 1 0 0 0 0
-1 0 0 0 0 0 0 1 0
-1 0 0 0 0 1 0 0 0
1 0 0 0 1 0 0 0 0
1 0 0 0 0 0 0 0 1
1 0 0 0 0 0 0 1 0
1 0 0 0 0 1 0 0 0

contrast2:
[1 0 0 0 0 0 0 0 0]

Thanks a lot,

Sean

Hi Sean,

these are not equivalent designs. The first design tests for a difference between a subset of samples, whereas the second design will test for a parametric effect - i.e. group  1 < group 2 < group 3. They will give different results.

For repeated measures designs, there needs to be repeated measure for all samples. For your exchange blocks, sample 8 only has one measurement. This is the most likely reason for the error. There are fancy ways to deal with missing repeated measures, but NBS assumes no missing data for all samples.

Andrew



Originally posted by Sean Froudist Walsh:

gotcha thanks