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Thread: Standard LCDM looking good...

  1. #1
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    Standard LCDM looking good...

    Just published: "Extensions beyond the standard cosmological model are strongly disfavoured, even where they are introduced to explain tensions or anomalies." - Alan Heavens, et al.
    Everyone is entitled to his own opinion, but not his own facts.

  2. #2
    ... As with all analyses based on Bayesian Evidence, the final numbers depend on the widths of the parameter priors.

    https://arxiv.org/abs/1704.03467
    ... the Bayesian probabilist specifies some prior probability, which is then updated to a posterior probability in the light of new, relevant data (evidence).

    https://en.wikipedia.org/wiki/Bayesian_probability
    I'm comfortable with that despite the slight suggestion of circular logic.

    If you don't see the suggestion, then I think that a good indicator of how slight it is.
    Last edited by Canis Lupus; 2017-Apr-13 at 06:55 AM.

  3. #3
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    Quote Originally Posted by Canis Lupus View Post
    I'm comfortable with that despite the slight suggestion of circular logic.
    It is not circular logic. Take a look at table one - they are generally very broad distributions or parameters constrained in a relatively model independent way. It would be circular if the priors were picked arbitrarily such that one or more of the models they were testing (the paper is not trying to exclude all possible models, just a set of extensions to the standard models) were excluded and then the conclusion was that these models were excluded by the analysis. They've been fairly careful, it appears, in how they set their priors (usually using Planck ones which were picked to allow a wide range of models to be tested) precisely to avoid their results being too sensitive to their inputs. They have also performed robustness analysis to see how much of an effect the priors have.

    In short - not circular, although as they make fairly clear set up to only test some possibilities and unable to exclude every model.

  4. #4
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    Quote Originally Posted by Cougar View Post
    Just published: "Extensions beyond the standard cosmological model are strongly disfavoured, even where they are introduced to explain tensions or anomalies." - Alan Heavens, et al.
    Impressive paper. Thanks.

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