Pearsons r question

#1
I’m getting correlation values to see correlation between parameters using two different methods. For almost all parameters this is working great. One parameter has an inherently low range, so my r values are low even though both methods are within an acceptable range and considered comparable. Is there a better way to look at correlation for parameters with low ranges like this?
 

hlsmith

Omega Contributor
#2
Parameter: means, standard deviation, etc.. Is this what you are writing about or do you mean variables? You usually select your method based on the variables. Two continuous variables, Pearson; two ordinal variables, Spearman,..., etc.
 
#3
The variable is what I mean. I know the blood pressure range is between 115-120. Both methods are within this range so I know they are correct. Problem is they are a bit “bouncy” within this range so the r is low. I’m trying to figure out a way to show that both methods are the same. I’m not sure about bland altman because I have over 100 subjects with multiple timepoints, most with this issue.