h · Planck constant

플랑크 상수

Takeaway

The relative standard uncertainty fell by a factor of about 617 from the 1969 to the 2014 edition (7.5×10⁻⁶ → 1.2×10⁻⁸): the error bars narrowed that much.
Of 8 earlier editions with a measured value, 7 have the 2022 value outside ±1σ (the error bar) and 4 outside ±2σ (the bar doubled); the normal expectation is about 1 in 3 and 1 in 22. The 2022 value is exact.
The largest move between editions came in 1973→1986, at 2.8 times the combined standard uncertainty of the two editions (|z| = 2.8).
Exact from the 2018 edition (fixed by definition rather than measured), so its uncertainty is zero.

Value ±1σ by edition2022

Relative deviation from the 2022 value (symmetric-log axis). Open circles: the error bar does not reach the 2022 value. Squares: exact.

Editionyear of the recommended values (data cut-off)	As printedexactly as in the source table; digits in parentheses are the standard uncertainty in the last digits	Standard uncertaintyhalf-width of the error bar (±1σ)	Relative standard uncertaintystandard uncertainty ÷ \|value\|: bar width relative to the value	Exactfixed by definition, uncertainty zero	z vs previous editionmove from the previous edition ÷ combined standard uncertainty of the two	z vs 2022(2022 value − this value) ÷ this edition's standard uncertainty	Source locationpage and table of the paper, or file and line of NIST's table
1969	6.626196(50) e-34	5.0×10⁻³⁹	7.5×10⁻⁶			−2.5170	477 table XXXII
1973	6.626176(36) e-34	3.6×10⁻³⁹	5.4×10⁻⁶		−0.3246	−2.9403	718 table 33.1
1986	6.6260755(40) e-34	4.0×10⁻⁴⁰	6.0×10⁻⁷		−2.7746	−1.3375	codata86 p.8 table 2
1998	6.626 068 76(52) e-34	5.2×10⁻⁴¹	7.8×10⁻⁸		−1.6709	2.6731	1998 ASCII:246
2002	6.626 0693(11) e-34	1.1×10⁻⁴⁰	1.7×10⁻⁷		0.4438	0.7727	2002 ASCII:247
2006	6.626 068 96(33) e-34	3.3×10⁻⁴¹	5.0×10⁻⁸		−0.2961	3.6061	2006 ASCII:248
2010	6.626 069 57 e-34	2.9×10⁻⁴¹	4.4×10⁻⁸		1.3885	2.0000	2010 ASCII:261
2014	6.626 070 040 e-34	8.1×10⁻⁴²	1.2×10⁻⁸		1.5609	1.3580	2014 ASCII:261
2018	6.626 070 15 e-34			yes			2018 ASCII:270
2022	6.626 070 15 e-34			yes			2022 ASCII:271