The trend is down

When we saw the dramatic surge in cases of coronavirus in 1st April, up from 179 to 430, many of us feared the worst. I did.

Then when it fell for the next two days, I hoped. Then when it went up and down for four days, I wasn’t sure what to think.

Drawing the graph helped to suggest that April 1st was a peak but the trend isn’t that clear based on just how it looks.

However, when you group the data in blocks of 3 or 4 days and generate daily averages you get something more explicit. Starting today and working back to the 1st, we get:

884 in last 3 days

Average: 295

1 035 in previous 3

Average: 345

or

1 228 in last 4 days

Average: 307

1438 in previous 4

Average: 359

The coronavirus outbreak is under control as long as we keep the lockdown?

13 thoughts on “The trend is down

  1. If you used centred moving average over does it give anything seemingly different?

    I am a microbiologist so we tend to have multiple samples and CMA helps as well

    Liked by 1 person

      1. John, if you look at the two charts from:
        https://www.travellingtabby.com/scotland-coronavirus-tracker/
        that have ‘new cases by day’ and ‘new deaths by day’, they show a 5-day average line on top of the bar chart that sort of gives an equivalent to what is being discussed here – just plagiarise the graphs (fully downloadable in jpeg and all sorts).

        I am beginning to suspect you’ve not had much practice with graph-drawing…

        Like

    1. You got there first 🙂

      The reporting system is quite noisy with the daily reports containing data missing from previous days, for whatever reason. To even out the noise, a rolling / moving average should provide a clearer picture – and it is quite easy to maintain.

      Liked by 1 person

    2. Like this?

      awk -F, ‘BEGIN {prev=0; ddn[-1] = 0;ddn[0] = 0; num=1} $1 ~ /^20/ {td=$4; id=td-prev; prev=td; ddt[num] = $1; ddn[num] = id; ++num;}; END {ddn[num]=ddn[num-1];for(idx=1; idx<num; ++idx){s=idx-1;val=(ddn[s]+ddn[s+1]+ddn[s+2])/3; val=int(val+0.5);print ddt[idx], ddn[idx], val}} ' < Scotland.csv

      giving:

      2020-03-11 0 0
      2020-03-12 0 0
      2020-03-13 1 0
      2020-03-14 0 0
      2020-03-15 0 0
      2020-03-16 0 0
      2020-03-17 1 1
      2020-03-18 1 2
      2020-03-19 3 1
      2020-03-20 0 1
      2020-03-21 1 1
      2020-03-22 3 3
      2020-03-23 4 3
      2020-03-24 2 4
      2020-03-25 6 4
      2020-03-26 3 6
      2020-03-27 8 6
      2020-03-28 7 5
      2020-03-29 1 5
      2020-03-30 6 7
      2020-03-31 13 12
      2020-04-01 16 26
      2020-04-02 50 37
      2020-04-03 46 47
      2020-04-04 46 31
      2020-04-05 2 17
      2020-04-06 2 26
      2020-04-07 74 50

      Being: Date, daily deaths, Calculation

      Where Calculation is the mean of the number of deaths on the 3 days centered on the date.

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  2. John

    Tempting fate, you could remove that final question mark.

    There’s a definite downward trend and as you say it should continue providing we keep the lockdown going.

    I see Bugger is French encore.

    Liked by 1 person

  3. Some simple figures on the number of ICU beds we have available still in scotland:

    We don’t want anyone to get to the stage of intensive care, so let’s hope the ones still unused stay unused, and recovery for those using them now.

    There is always a delay John, people don’t get the serious symptoms immediately – I think Boris’ deterioration is more typical, if you start feeling worse after 10 days you’ll probably be needing help breathing. So, if we started lockdown two weeks ago and it was spreading before that, it will just be about now the majority of people will either start feeling better or start getting worse, then the latter group will start hospital treatment and a portion of them will become more ill over the course of weeks(?) – so the prediction that there will be a spike over the next two weeks is a reasonable one (assuming a lot of people caught it before the lockdown, but we don’t know that) – we don’t know of course, but a slower increase in deaths just now is a good sign.

    Liked by 2 people

  4. Contrary: ‘I am beginning to suspect you’ve not had much practice with graph-drawing…’

    I do my best. I’m hurt.

    I’m starting a campaign to have you renamed.

    Anyhoo, I’m dropping it for clustered averages,

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      1. Misleading? That’s the data that’s out there – the bar chart shows daily deaths as reported, but then he keeps a rolling 5-day average (remember them) to ‘smooth’ the curve – what is misleading about that? You can pick and choose your own ways to present the data…

        And its the number of days for death to double (where he takes a 3-day average for calcs) that is the best indicator of things out of control – we’re doing not bad with 3.9 days for doubling (in the green on his graph).

        Emoticon usage was just in case you didn’t know the meaning of ‘clustered’ or ‘average’ and didn’t get my very hilarious joke … um, I’m in more trouble now amn’t I?!

        Like

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