Looking at gold chart from year 2000 until now, we can see couple of rises in gold price.
[row 1] 1st rise was from 400 to 740 (185%). Then it corrected to 590 (25%).
[row 2] 2nd rise was from 590 to 1000 (169%) and corrected to 790 (27%).

[row 3] We believed that the third rise was from 790 to 1200 (152%) and corrected back to 1150 (4%).

However nor the rise, nor the decline is “similar” to previous rises.

[row 3] Thats why we may think that the third rise was from 790 to 1390 (176%) and that the correction is underway now. If correction is 27%, then gold must correct \$375 down to 1015.

Another study could be, to see, what are percentage differences between the rises (in the table it is called “% from previous up”) :

[row 2] From 1st to 2nd we have 740 to 1000 = 35%
[row 3] From 2nd to 3rd we have 1000 to 1200 = 20%
[row 3a] From 2nd to 3rd-a we have 1000 to 1200 = 39%

Once again [row 3a] is more “similar”.

Another study, not shown here could be % from previous bottom.

[row 2] From 1st to 2nd we have 590 to 790 = 34%

[row 3] From 2nd to 3rd we have 790 to 1150 = 46% (not very likely)
[row 3a] From 2nd to 3rd-a we have 790 to 1015 = 39% (more likely)

Note this study uses the hypotetical bottom from previous study.
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Update:

If we extend the current rally to 1450, this could give us following data:

Rise % = 184%

Correction % = 27% (from previous study)
% from previous up = 45% (bit much)
% from previous bottom = 34% 