Pearsons r question

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?


Not a robit
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.
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.