Question re BGR and WGR values and effects (case 387)

[jarvis24]

It's actually a bit more flexible than it would be if WGR values had to be kept within BGR blocks. In some cases, a user might want to randomize items from outside the blocks. For that reason, all the items sharing the same WGR values will be randomed with each other--i.e., we're talking about all of the items in the whole input file.

In your illustration, you would be seeing trials from block 2 being mixed with those in block 1, because they share common WGR values. To avoid that result, you could use unique WGR values within each block. That would prevent any crossover.

e.g., try it like this and see if you get the desired result.

block trial bgr wgr
1 1 1 1
1 2 1 1
1 3 1 1
1 4 1 1
2 5 2 2
2 6 2 2
2 7 2 2
2 8 2 2

With regard to the naming convention (WGR/BGR vs RWG/RBG), a quick search on the forums seems to clearly indicate that we have standardized with the use of WGR/BGR. I will adjust the documentation accordingly. Thanks for pointing that out. I think the same thing applies to MediaLab.

[jzadra]

With regard to the naming convention (WGR/BGR vs RWG/RBG), a quick search on the forums seems to clearly indicate that we have standardized with the use of WGR/BGR. I will adjust the documentation accordingly. Thanks for pointing that out. I think the same thing applies to MediaLab.

FYI, I found this thread after being confused by the tutorial documentation that came with DRT 2012, which still refers to RWG/RBG.