Project Sign and Blue Book scientific interpretation era
In the 1950s and early 1960s, Project Blue Book inherited the UFO intake chain begun under Project Sign, while public officials continued to balance national security scrutiny against open scientific interpretation.12 McDonald drew direct attention to this transition by arguing that unresolved sightings needed more rigorous scientific interpretation and not only summary classification.34
Observational role and evidence collection
After a two-year period of intensive work, McDonald traveled in 1967 through Australia, Tasmania, and New Zealand to interview approximately 80 witnesses, then incorporated those reports into broader comparative analysis.5 He documented atmospheric, radar, and witness-based cases and remained focused on observations from trained or credible observers when considering explanations for unidentified phenomena.56
Testimony and later evidence evaluation
At the 1968 House Committee on Science and Astronautics UFO symposium, McDonald presented a prepared statement and Q&A reflecting persistent concern about weak evidentiary standards in official reviews and calling for expanded scientific study of case records and witness material.7 His position is echoed in later formal records that framed evidence review around improved investigation procedures and scientifically defensible case triage.38