Amount of edit after submission (conference paper) I will be submitting a conference paper that proposes a new method for analysing a particular kind of data within the next 2 weeks. However, I think that I may improve the method slightly during the following 4 weeks that the reviewers use before giving feedback. The improvements will be minor, but it would be nice to include. It is out of the question to wait with submission for another conference based on this potential improvement.

Is it okay to simply replace the old results with the new results if the results improve after submission? More generally, how much can one add to a conference paper after it has been submitted? Is it only allowed to add elements that the reviewers request?
The general rule of thumb for conference papers is that nothing you add should be such that it would cause a reviewer to worsen their opinion of the paper.  That's a very fuzzy boundary, though, and it's certainly possible for somebody to make changes that would be considered too much.  Moreover, such changes would likely go unnoticed for most conferences, since there is often little checking of differences between the initial and final versions, except in the case of borderline papers.

Personally, I tend to use the following rubric to decide:


Are the changes a strict improvement?  Sometimes improving one aspect causes degradation in others, and that's not OK.
Is the improvement worth its own paper?  Post-acceptance additions should be incremental only.
Will adding new material require dropping anything else significant?  Conference papers often have strict page limits, and new material should not displace material important for acceptance.


What you describe sounds likely to pass this rubric.  Even if it does not, however, remember that in fields with peer-reviewed conference publications you can typically publish an "extended version" as a journal paper.  Such extended versions are an excellent place for any incremental improvements too large or too late for the conference version to go.