I'm doing data analysis on the results of several trials of an experiment. I took detailed notes on every run but the first one (my supervisor and I did this together as a demonstration run). As I'm looking at the data, all the runs seem to agree with each other quite well, except for the first run, where every single data point is shift down by a considerable and consistent margin. Because I don't have any information on this run, I'm thinking to just pitch the data. However, this is also the first run we did together, which makes me wonder if I've been fucking up every other run. Thoughts? Should I exclude the run from analysis? Supervisor is out today otherwise I'd ask him