Click Here for Tools pageAnalysis of Competing Hypotheses (ACH) is an analytic process that identifies a complete set of alternative hypotheses, systematically evaluates data that is consistent and inconsistent with each hypothesis, and rejects hypotheses that contain too much inconsistent data. It is a simple model for how to think about a complex problem. The ACH methodology was developed by Richards J. Heuer, Jr.The method for analyzing competing hypotheses takes time and attention in the initial stages, but pays big dividends in streamlining management and coordination of analytic positions. ACH is particularly useful for issues that require a careful weighing of alternative explanations of what has happened or is happening. It can also be used to provide early warning or to help you evaluate alternative scenarios of what might happen in the future.ACH helps you overcome, or at least minimize, some of the cognitive limitations that make prescient intelligence analysis so difficult; it helps clarify why analysts are talking past one another and do not understand each other’s interpretation of the data. ACH is grounded in basic insights from cognitive psychology, decision analysis, and the scientific method. It helps analysts protect themselves from avoidable error and improve their chances of making the right call.

You can download the ACH software tool from here. Please see below if you would like to practice using the ACH tool. The following articles provide more information about ACH and its value for intelligence analysis:

TH!NK Suite®, Multiple Hypotheses Generator™, Te@mACH™ and Indicators Validator™ are registered trademarks of Globalytica, LLC

Practice Using ACH!

If you want to try out the ACH software, follow these instructions:

  1. Download the software following the instructions above.
  2. Click on this link to download the practice case study, The Wen Ho Lee Case Study.
  3. As you read the case study, ask yourself two questions:
    • What hypotheses would explain Wen Ho Lee’s behavior?
    • What information or evidence in the case study would help determine which hypotheses are most likely to be true?
  4. Click on this link to download a practice ACH matrix, The Wen Ho Lee ACH matrix.
    • For your convenience, 13 evidence points have been pre-entered; you can still add more points of evidence.
    • You should enter at least three hypotheses across the top of the matrix (under H:1, H:2, H:3).
  5. Fill out the matrix by selecting a cell and choosing the appropriate value with the pull down menu.
  6. After you have filled out the matrix, go to the top of the sheet and in the box that says Sort Evidence By: click on Diagnosticity. The diagnosticity function will sort your hypotheses from most to least likely and your evidence from most to least discriminating.
  7. If you want feedback on how well you did, send us an email message to and attach a copy of your completed matrix.
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Globalytica, LLC, an affiliate company of Pherson Associates, has developed several simple, but elegant, web-based tools that enhance an analyst’s critical thinking skills. This toolbox of computer-assisted analytic techniques allow analysts to generate multiple hypotheses, validate scenario indicators, and use the Analysis of Competing Hypotheses Methodology in a collaborative, web-based environment.

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