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- Peaks that are very broad or not sharp enough (see for example Sweden).
- Peaks which consist of multiple sub-peaks where the sub-peaks for say confirmed cases do not match those for deaths (see for example Hong KongKong or Mexico).
- Peaks in deaths that appear to precede the confirmed cases (see for example Tajikistan)
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- Countries with sudden step increases in the confirmed cases or deaths or both, presumably to catch up on missed data entry for the country (see for example Ecuador and Kyrgzstan)
- Countries with low statistics, especially for deaths (see for example Taiwan).
- Countries with no deaths reported (see for example Cambodia and Laos).
If one takes the statistics of the Diffs they are seen below:
| Statistic | Diff[0] | Diff[1] | Diff[2] | Diff[3] | All |
| Count | 38 | 15 | 2 | 1 | 56 |
| Average | 7.1232687 | 4.50666667 | 4 | 14.3571429 | |
| Stdev.a | 16.7652396 | 5.50064931 | 5.65685425 | 14.1439721 | |
| Median | 16.7652396 | 5.50064931 | 4 | 12.5 | |
| 1st quartile | 9.25 | 9 | 14 | 6 | 9 |
| 3 rd quartile | 15 | 16.5 | 18 | 6 | 15.25 |
| Inter Quartile Range | 5.75 | 7.5 | 4 | 6.25 |
The images below show the time series of confirmed cases (solid line) and deaths (dashed line) for representative countries and regions of the world. We choose these countries since they have large numbers of confirmed cases, and are expected to have a reasonably good accounting of the cases. The Diff is the approximate number of days prominent matching features in the time series (e.g. peaks, valleys and slopes) of the two cases. In many, but not al all cases we identify the matching structures and the Diff in days. You can click on an image to blow up its size and see details.
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