Analysis of Competing Hypotheses (ACH)

Analysis of Competing Hypotheses (ACH)

What It Is: A highly structured process for evaluating multiple competing hypotheses against all available evidence. It is designed to avoid the common pitfall of selecting a preferred hypothesis and only seeking confirming evidence.

When to Use It: For complex issues where there are multiple possible explanations and a high volume of evidence.

Step-by-Step Guide:

1. STEP 1: List hypotheses to be considered. (Beebe and Pherson, 2015, p. 209)
2. STEP 2: Assess information for consistency with each hypothesis. (Beebe and Pherson, 2015, p. 209)
3. STEP 3: Refine hypotheses and conclusions based on inconsistencies. (Beebe and Pherson, 2015, p. 210)

ACH Matrix Template:

Evidence/Arguments	H1	H2	H3	H4	H5
Evidence/Argument 1	C	I	N	C	I
Evidence/Argument 2	N	C	I	I	C
Evidence/Argument 3	I	N	C	C	I
Evidence/Argument 4	C	C	N	I	N
Evidence/Argument 5	I	N	C	I	C
Total Inconsistencies	X	Y	Z	A	B

Key: C = Consistent, I = Inconsistent, N = Neutral

Tentative Conclusion: The hypothesis with the fewest inconsistencies is the most likely.

(Pherson and Heuer, 2021, p. 245)