All these possible sources of error can't amount to much.

So far, we have only considered scientific sources of error.

It is not possible to eliminate all sources of error.

Yes, there lay the source of error in our former division.

There are several potential sources of error in such data collections.

They're bound to lead us to the sources of error which we can then take a look at ourselves.

Several sources of error are effectively beyond researchers' capacity to control.

This may introduce a source of error into the poll.

The order of questions is another source of potential error.

You did not describe your experiment so it's hard to suggest sources of error.