Dear all,
normally I tend to stay out of these debates, but a different view is
given in this other review of resolution measures
(http://i2pc.es/coss/Articulos/Sorzano2017.pdf), around Eq. 77. In my
opinion, the 1/2 bit threshold is not well founded, while the other
thresholds they all have their reasoning (see Section 5 of that review).
However, I agree with Marin that reducing a map to a single number is
doing poor justice to the structural information inside.
Kind regards, Carlos Oscar
On 24/11/2017 23:46, Marin van Heel wrote:
>
>
> Dear All,
>
> Impressive as the cryo-EM results of the resolution resolution may be,
> a fundamental statistical error has persisted in the literature that
> affects almost all cryo-EM quality metrics (FSC-0.143, FSC 0.5; DPR
> 45, SSNR, Gold Stardust FSC, etc ...) One of the very few survivors of
> this methodology onslaught is the FSC 1/2 bit criterion. The numerical
> resolution values for practically all published structures have no
> absolute meaning and can therefore not be compared to each other. The
> error goes back to a misinterpretation of basic statistics made in the
> 1970s and pervaded virtually all popular cryo-EM quality metrics. It
> may frustrate many of you to have to change your way of thinking or
> the programs you are using, but that is what science requires you to
> do now. Alternatively - following strict scientific standards - you
> can try prove us wrong with real scientific arguments (carefully read
> our paper before you start criticizing). Even if 99% of cryo-EM
> practitioners use incorrect metrics, that does not make the metrics
> right! Science is not a democracy ... We are of course aware that
> with this paper we are refuting a huge number of methodological papers
> all at once, with many people involved who will undoubtedly be left
> frustrated. If that is of any help, I also feel frustrated that it
> took me (us) far too long to get to the core of the matter so as to
> resolve these issues once and for all. On the positive side, we can
> now all be relieved of the eternal and repetitive FSC jokes at cryo-EM
> meetings!
>
> For now, good night and have a good weekend!
>
> Marin
>
> our BiorXiv contribution ca be found here:
> https://www.biorxiv.org/content/early/2017/11/24/224402
>
>
--
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Carlos Oscar Sánchez Sorzano e-mail: [log in to unmask]
Biocomputing unit http://i2pc.es/coss
National Center of Biotechnology (CSIC)
c/Darwin, 3
Campus Universidad Autónoma (Cantoblanco) Tlf: 34-91-585 4510
28049 MADRID (SPAIN) Fax: 34-91-585 4506
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