When you have LSMeans effects in your model , it is often of interest to compare differences among their levels using Volcano Plot s . Specify the set of differences that you want to consider.
• All Pairwise Differences denotes differences between all possible pairs of levels.
• Simple Differences denotes all differences for which only one level has changed.
• Differences with a Control denotes taking differences against a single reference level. You can specify this level in the next parameter ( LSMeans Control Levels ).Caution : All Pairwise Differences can generate numerous differences when there are many levels in your LSMeans effects.