If you’re faced with pressure about an analytical conclusion you’ve reached, it helps if you’ve based that conclusion on a strong analytical framework. If challenged, you can retrace the path that led you to your findings, and it will strengthen your case because structured techniques minimize bias and outside influence.
Several years ago, I was tasked with assessing a CCTV clip of an incident that occurred on a Metro platform. Investigators and fellow analysts who viewed the video saw one of two things: a group of up to five co-conspirators seeking to test security for a potential future attack; or, one person, who was behaving unusually, possibly recklessly, but not nefariously. It was my job to explain what happened.
I chose to analyze the video using the Analysis of Competing Hypotheses (ACH), a formal analytical technique that slows the thinking process and minimizes bias. I went into the assignment thinking the actions of the persons on the platform were indeed suspicious. Because I was already drawing a conclusion, it was especially important to pull myself out of that mindset and assess the situation from a neutral position. Hence, ACH.
The first step of ACH is brainstorming. What could explain the activity? I came up with at least 15 scenarios, then I narrowed my choices to five that appeared to be the most logical. I laid out the evidence and assessed it, one piece at a time, against each hypothesis.
After applying ACH, I was surprised the analysis found the activity captured on the CCTV was wholly innocuous.
Later, I participated in a conference call with analysts from Washington, DC. They pushed back strongly on my conclusion, saying the group was clearly testing security. I laid out my case methodically: all of the hypotheses I had considered, the evidence line-by-line, the inconsistencies of each theory, and how it all firmly pointed to harmless activity. They had no counterargument but that it “looked” suspicious.
Later, investigators located and interviewed the main subject. He was a transient with no ill intent.