People have been wondering why there is such difference between Polar Urals versions. In many cases, the archived Osborn and Briffa  version (smoothed) is consistent with the emailed Esper et al  version – but not always. It’s always worthwhile examining differences and here are a few.
Here the Esper et al  version looks like the Luckman  version archived at Briffa’s website and a mainstay of multiproxy studies. Osborn and Briffa use the updated version done by Luckman and Wilson  (not yet archived). The correlation between the two versions is only 0.27. Note the size of the differences around AD1400. Remember that the earlier version probably thought that it had a very tight confidence interval.
Figure 1. Jasper/Icefields versions. No archived measurements.
Foxtails are closely related to bristlecones (they interbreed and are on adjacent mountain ranges in California). I took the average of the two foxtail series in Esper; the average correlates closely (>0.99), but the Osborn-Briffa version does not include a high portion in the early 9th century. I’m sure that there’s a wonderful reason for this.
Figure 2. Average of Boreal and Upper Wright foxtails. No archived measurements.
I have no idea what they are doing here. Both Briffa and Osborn match, but they truncate the series in 1947. Contrary to speculation, the RCS version goes up after 1947.
Figure 3. Quebec (cana169). Esper et al.  had cited Filion and Payette, a different series.
Again, I am unable to fathom the provenance. Both Esper and Briffa seem to have the same version, but it’s inconsistent with germ21 (cited in Osborn and Briffa).
Figure 4. Tirol (germ21)
Here Esper and Briffa have somewhat different versions (correlation 0.81). Note that the 20th century is elevated in the Osborn and Briffa version relative to Esper – this will undobtedly shock everyone.
Figure 5. Tornetrask. Archive not consistent with report.
Obviously I’ve posted lots about this. The correlation between the two smoothed versions is 0.50.
Figure 6. Polar Urals/Yamal. Yamal not archived (but I have it)
Again, Osborn and Esper had virtually identical versions, but the dates and shape were incompatible with the archive references (russ067, russ068).
Figure 7. Mangazeja
The Esper and Briffa versions are very similar but not identical (correlation 0.94). There is perhaps some difference in RCS numerics.
Again the Esper and Briffa versions are similar but not identical (correlation 0.8). There is an archive beginning in 900, while both Esper and Briffa versions begin earlier.