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Message: <blockquote data-quote="Umbran" data-source="post: 8524707" data-attributes="member: 177">Or, (c) the wastewater signal isn't quite as direct or reliable an indicator as you might like.[spoiler="Data analysis discussion that might bore some folks"]Let us look at this graph:[ATTACH=full]150698[/ATTACH]The orange peak in the middle of the graph is April 8.  The green peak in the middle is about April 17th, with about 313 cases per day at that time.  We might take from this that there's a delay of a bit more than a week between wastewater signal and cases.But... what about that trough just before the peak?  That's a sharp, drop off from a high on March 10, to a super-low on March 22, before you see that huge spike on April 8th.  But, look at the case rate - if the wastewater is a clear indicator, we should see a massive drop in new cases at the end of March, and that's nowhere to be seen.  Cases are continuing to rise over that period.  Indeed, there's even a tiny bump up in cases about a week after that trough.A critical data analysis eye then reads that entire March-April trough and spike in the wastewater signal as hinkey (yes, that's a technical term).  It is almost like there was a something that preferentially held virus laden water in a reservoir for a while, and then released it later.  There are issues in data analysis or detectors that can also give rise to such.  I can't tell what's happening, but since the cases do not mirror that drop and spike, we should question the validity and/or meaning of it.So, for example, we could imagine that it wasn't a real thing, and did not happen, and that wastewater signal should have been more or less constant from about March 10th to April 20th - around 0.00075 normalized viral copies.Now, we look at more recent time.  Your ability to measure cases fell off a cliff in the beginning of the year, the cases are consistent with the wastewater signal until then. So, if we "correct" that April spike, in April we have a wastewater signal of 0.00075, and a peak of 313 cases per day.  Then, in late December we have a wastewater signal of about 0.0015, and cases up around 800.  Twice the wastewater signal, twice the cases.  Seems legit.So, overall, I question that April spike more than I question whether you guys have actually had a recent surge in cases. [/spoiler]</blockquote>

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