There are many synonymous phrases for "with small probability of error" that can be used to describe the accuracy of a process or outcome. Some alternative phrases include "high degree of precision," "negligible margin of error," "minimal chance of inaccuracies," "near-perfect accuracy," "impeccable precision," "almost infallible," and "exceptionally accurate." These synonyms can be used in a variety of contexts, including scientific research, engineering, and quality assurance testing. By using these alternative phrases, writers can add variety to their language and convey the same precise meaning in different ways.