A question that we often get asked often is about the precedents for the re-identification risk threshold. There is actually a lot of precedents. We recently included a literature review of these precedents and published that as an appendix to one of our papers.
The appendix with that review of precedents is here (it is Appendix B).
The paper itself is about measuring privacy risks in synthetic data and is here for those who are interested.
Since the completion of that review, the ISO standard was published and this also establishes a strong precedent for re-identification risk thresholds. The ISO standard can be obtained (purchased) from here.