I'm new to Ribo-Seq and trying to understand how the analyze the data. I have difficulties understanding what the offset means. I know it is defined as the distance between the start of the read at the 5'-end and the P-site, which is inside the ribosome.
But how is this offset calculated? why do I have sometimes different offset values for different read lengths, but sometime not and why do i use different offsets for the same read length in different data sets? Is there a tutorial or a workflow explaining this approach?