Busting Calls: CQ WW 2025

 Prior posts in this series:

• Initial analysis
• Further analysis
• CQ WW SSB 2005 to 2016 
• CQ WW CW 2005 to 2016
• Non-Run QSOs, CQ WW 2005 to 2016
• Run QSOs, CQ WW 2005 to 2016
• 2017, 2018
• 2019
• 2020
• 2021
• 2022
• 2023  
• 2024

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Throughout this post, I apply the procedures developed in the second post above.

For the purpose of this post, only verified QSOs are counted.

Lowest Probability

I begin with an ordered list of the stations with the lowest probabilities of busting a call in 2025 CQ WW SSB.

2025 CQ WW SSB -- weighted mean values of $p_{bust}$ (all)
Position	Call	weighted mean	$Q_v$	$B$
1	G4NBS	0.0009	1,072	0
2	AD1C	0.0010	978	0
3	WE6Z	0.0010	974	0
4	SE4E	0.0010	960	0
5	WH7T	0.0010	1,969	1
6	N1WR	0.0011	891	0
7	NF3R	0.0011	890	0
8	DL7URH	0.0011	844	0
9	DL1YAW	0.0011	834	0
10	F8CRS	0.0012	779	0

And for 2025 CQ WW CW:

2025 CQ WW CW -- weighted mean values of $p_{bust}$ (all)
Position	Call	weighted mean	$Q_v$	$B$
1	IK2XDE	0.0006	1,631	0
2	RX7T	0.0007	1,396	0
3	F8DBF	0.0007	1,303	0
4	JE1NVD	0.0007	1,255	0
5	N7IR	0.0009	1,109	0
6	9A2X	0.0009	1,091	0
7	UA3AP	0.0009	1,077	0
8	UA3MIF	0.0009	1,034	0
9	DL4FN	0.0010	990	0
10	DF2RG	0.0010	985	0

It is interesting to plot the aggregated probability function for $p_{bust}$ weighted by the verified number of QSOs, $Q_v$, for all stations:

In case it isn't clear, in the figure above the location of the solid vertical lines represent the weighted means of the probability curves. In 2025, then, there was little difference between these curves for CW and SSB.

We can limit the analysis to calling stations (i.e., not the running station).

2025 CQ WW SSB -- weighted mean values of $p_{bust}$ (no-run)
Position	Call	weighted mean	$Q_v$	$B$
1	DJ4MX	0.0005	1,851	0
2	DR4A	0.0006	1,435	0
3	W1GD	0.0008	1,203	0
4	G4NBS	0.0009	1,060	0
5	OE6MDF	0.0009	1,039	0
6	DP9A	0.0009	1,034	0
7	AD1C	0.0010	975	0
8	SE4E	0.0010	954	0
9	WJ1U	0.0010	940	0
10	MM1U	0.0011	883	0

2025 CQ WW CW -- weighted mean values of $p_{bust}$ (no-run)
Position	Call	weighted mean	$Q_v$	$B$
1	N2AA	0.0004	2,053	0
2	DL3YM	0.0005	1,935	0
3	SP2LNW	0.0008	1,210	0
4	RX7T	0.0008	1,206	0
5	RA3AN	0.0008	1,136	0
6	N4QS	0.0008	1,134	0
7	JE1NVD	0.0009	1,075	0
8	YO4NF	0.0009	1,066	0
9	IK2XDE	0.0009	1,060	0
10	N2GC	0.0009	1,040	0

  And similarly for running stations: 

2025 CQ WW SSB -- weighted mean values of $p_{bust}$ (run)
Position	Call	weighted mean	$Q_v$	$B$
1	WM9C	0.0007	1,415	0
2	WH7T	0.0011	1,891	1
3	9M8DEN	0.0011	892	0
4	DJ5MW	0.0017	2,399	3
5	IT9STX	0.0017	1,197	1
6	VE7BC	0.0017	1,725	2
7	K8GL	0.0018	538	0
8	TI1K	0.0019	2,149	3
9	LA8HGA	0.0019	516	0
10	YT4L	0.0019	500	0

2025 CQ WW CW -- weighted mean values of $p_{bust}$ (run)
Position	Call	weighted mean	$Q_v$	$B$
1	S57KM	0.0011	834	0
2	F8DBF	0.0013	741	0
3	W3FIZ	0.0015	642	0
4	OE5TXF	0.0015	1,309	1
5	KR2Q	0.0015	628	0
6	NH6V	0.0016	587	0
7	W4EF	0.0017	582	0
8	IK2XDE	0.0017	571	0
9	UN4Q	0.0018	2,233	3
10	I4IKW	0.0019	524	0

We can also look at the changes over the period from 2005 to 2025.

First for all QSOs:

Then for calling stations:

And for running stations:

The clear up-tick on CW in 2023 is rather interesting. At first, I thought that it might be due to people logging calls mis-spotted on the various spotting networks. But its presence when one limits the analysis to running stations would seem to make that theory untenable. Perhaps it is due to an increase in entrants using code readers, although one would expect few runners to be using those. So this might be an interesting area for further analysis, should anyone be interested. It really is a quite remarkable year-on-year change -- and especially so, given that whatever caused the uptick seems to have gone away. Very odd.

I think it's also interesting to see who appears to have the lowest probability of busting a call over an extended period. So, for the ten years 2016 to 2025:

2016--2025 CQ WW SSB -- weighted mean values of $p_{bust}$ (all)
Position	Call	weighted mean	$Q_v$	$B$
1	OK1WCF	0.0005	1,726	0
2	OH7GGX	0.0006	3,287	1
3	UT7W	0.0006	1,466	0
4	LU1FAM	0.0007	1,400	0
5	K4RUM	0.0007	1,339	0
6	DL5AXX	0.0007	1,308	0
7	JM1NKT	0.0007	1,270	0
8	K9PG	0.0008	2,634	1
9	KT4O	0.0008	1,225	0
10	AD1C	0.0008	3,875	2

2016--2025 CQ WW CW -- weighted mean values of $p_{bust}$ (all)
Position	Call	weighted mean	$Q_v$	$B$
1	NW0M	0.0002	5,084	0
2	K9PW	0.0003	2,935	0
3	N7IR	0.0003	2,923	0
4	UN4PD	0.0003	2,914	0
5	JR3RWB	0.0004	2,404	0
6	K6WSC	0.0004	5,108	1
7	AD1C	0.0004	5,089	1
8	JN3SAC	0.0004	4,691	1
9	N0BK	0.0005	1,853	0
10	DP4X	0.0005	4,132	1

A good argument can be made that a better measure of copying ability is to consider only run QSOs:

2016--2025 CQ WW SSB -- weighted mean values of $p_{bust}$ (run)
Position	Call	weighted mean	$Q_v$	$B$
1	LU1FAM	0.0007	1,353	0
2	C6ARW	0.0010	1,925	1
3	BV2A	0.0010	913	0
4	OM0WR	0.0012	1,734	1
5	F4FTA	0.0012	828	0
6	DL8RDL	0.0013	748	0
7	CF7RR	0.0013	1,557	1
8	CR2X	0.0014	2,169	2
9	TK9R	0.0014	13,326	18
10	SP9XCN	0.0015	2,663	3

2016--2025 CQ WW CW -- weighted mean values of $p_{bust}$ (run)
Position	Call	weighted mean	$Q_v$	$B$
1	LY3CY	0.0005	1,873	0
2	RA3TT	0.0006	1,530	0
3	JN3SAC	0.0007	1,371	0
4	R2VM	0.0009	1,040	0
5	DL1NEO	0.0009	2,200	1
6	E72U	0.0009	4,298	3
7	WB4TDH	0.0009	3,212	2
8	RG5A/6	0.0010	959	0
9	ZR2A/4	0.0010	951	0
10	G5Q	0.0010	936	0

Highest Probability

We can also look at the calls associated with the highest probability of busting calls in either the forward or the reverse direction:

2025 SSB -- Most Busts
Position	Call	QSOs	Busts	% Busts
1	CN3A	15,367	232	1.5
2	II9P	11,251	208	1.8
3	VP2MPN	5,589	195	3.5
4	RU1A	11,373	179	1.6
5	A44A	6,224	178	2.9
6	RK4FD	6,124	175	2.9
7	V26B	11,705	173	1.5
8	ES9C	15,335	161	1.0
9	PR1T	6,919	161	2.3
10	9Z4BM	4,317	155	3.6

2025 CW -- Most Busts
Position	Call	QSOs	Busts	% Busts
1	CN3A	15,265	242	1.6
2	PJ2T	11,405	208	1.8
3	F6KOP	7,694	185	2.4
4	TK0C	15,959	171	1.1
5	VP2MMA	4,701	171	3.6
6	ZF5T	12,366	164	1.3
7	ES9C	13,275	159	1.2
8	RW0A	6,902	149	2.2
9	JA3YBK	5,735	140	2.4
10	ED1R	8,700	138	1.6

2025 SSB -- Highest Percentage of Busts (≥100 QSOs)
Position	Call	QSOs	Busts	% Busts
1	YB1BML	110	22	20.0
2	PU2NZO	103	19	18.4
3	PY3AN	131	24	18.3
4	DX9CHR	101	17	16.8
5	EA4HWF	110	18	16.4
6	UR5ZDZ	159	25	15.7
7	YB9JIP	100	14	14.0
8	IS0AGY	113	15	13.3
9	JH1CML	405	50	12.3
10	BA7OOJ	203	25	12.3

2025 CW -- Highest Percentage of Busts (≥100 QSOs)
Position	Call	QSOs	Busts	% Busts
1	LA100A	131	73	55.7
2	F5MBM	107	23	21.5
3	IZ5FSA	104	20	19.2
4	YT0B	268	49	18.3
5	YO9CX	102	18	17.6
6	OK2CMZ	122	21	17.2
7	WF1A	254	43	16.9
8	W6UB	240	40	16.7
9	S51SL	259	43	16.6
10	CX2CC	205	34	16.6

2025 SSB -- Most Reverse Busts
Position	Call	QSOs	Reverse Busts	% Reverse Busts
1	DF0HQ	11,151	418	3.7
2	ES9C	15,335	369	2.4
3	TM2Y	5,258	317	6.0
4	RK4FD	6,124	316	5.2
5	RU1A	11,373	279	2.5
6	F6KOP	6,838	270	3.9
7	CQ3W	3,479	212	6.1
8	K3LR	10,761	209	1.9
9	UA7K	12,752	208	1.6
10	AB3AH	2,169	200	9.2

2025 CW -- Most Reverse Busts
Position	Call	QSOs	Reverse Busts	% Reverse Busts
1	5J1DX	7,827	597	7.6
2	ES9C	13,275	440	3.3
3	KP2B	6,104	367	6.0
4	IP2A	8,332	321	3.9
5	M6T	12,125	283	2.3
6	TK0C	15,959	261	1.6
7	KB4DX	4,330	248	5.7
8	RM9A	8,933	233	2.6
9	UA7K	11,338	233	2.1
10	PJ4K	12,714	228	1.8

2025 SSB -- Highest Percentage of Reverse Busts (≥100 QSOs)
Position	Call	QSOs	% Reverse Busts
1	BH3AGU	176	15.3
2	ZW2L	463	13.2
3	BI8AQ	720	12.1
4	VU3FWG	593	12.0
5	HB2Y	427	11.9
6	BH8GFN	1,329	11.2
7	IZ2LQD	144	11.1
8	XE1ADY	1,197	10.9
9	BD4SDX	1,083	9.5
10	SP9MAT	201	9.5

2025 CW -- Highest Percentage of Reverse Busts (≥100 QSOs)
Position	Call	QSOs	% Reverse Busts
1	PDR4	156	100.0
2	IV3WMI	371	29.1
3	F4LTV	199	26.1
4	K7HV	125	21.6
5	UB4WCY	194	14.9
6	DG2SER	100	13.0
7	SA6LKX	166	12.7
8	4X5DK	106	12.3
9	DF8JK	164	12.2
10	WT1A	246	12.2

In tables of reverse busts, one sometimes finds what seems like an unreasonable number of reverse busts. This is generally caused by a discrepancy between the call actually sent by the listed station and the one recorded as being sent in at least some QSOs in the station's log (as is the case, for example, for "PDR4" in the CW table above: that was the "sent" call listed for every QSO in PD4R's log). Other causes of frequent reverse busts are poor sending/audio, unusual calls and calls that are very similar to the call of an active, well-known contester whose call appears in the various databases that can be found on the Internet.

Looking at a ten-year period:

2016--2025 SSB -- Most Busts
Position	Call	QSOs	Busts	% Busts
1	CN3A	98,729	1,617	1.6
2	LZ9W	98,398	1,544	1.6
3	OT5A	60,647	1,307	2.2
4	PJ2T	75,526	1,224	1.6
5	V26B	69,821	1,155	1.7
6	YT5A	78,252	1,098	1.4
7	CR6K	68,133	1,042	1.5
8	CQ8M	32,382	959	3.0
9	II2S	63,855	952	1.5
10	M6T	79,758	926	1.2

2016--2025 CW -- Most Busts
Position	Call	QSOs	Busts	% Busts
1	TK0C	91,763	1,279	1.4
2	PJ2T	95,008	1,244	1.3
3	LZ9W	106,154	1,193	1.1
4	CN3A	82,045	1,151	1.4
5	F6KOP	39,906	1,069	2.7
6	JA3YBK	49,340	1,037	2.1
7	YT5A	92,617	971	1.0
8	M6T	96,972	941	1.0
9	PI4CC	40,660	896	2.2
10	RW0A	46,515	884	1.9

2016--2025 SSB -- Highest Percentage of Busts (≥500 QSOs)
Position	Call	QSOs	Busts	% Busts
1	IS0AGY	751	114	15.2
2	YB2BNN	632	87	13.8
3	OH1TS	749	95	12.7
4	UR5ZDZ	1,218	120	9.9
5	R9MBY	773	76	9.8
6	EA4GWL	931	91	9.8
7	LU4DJB	672	64	9.5
8	JH1CML	1,227	116	9.5
9	E20WXA	688	64	9.3
10	EA1HTF	1,526	139	9.1

2016--2025 CW -- Highest Percentage of Busts (≥500 QSOs)
Position	Call	QSOs	Busts	% Busts
1	KL7NL	550	111	20.2
2	DJ5UZ	586	117	20.0
3	SP2EPV	510	93	18.2
4	DL7CO	827	140	16.9
5	CE6VMO	695	111	16.0
6	LZ1BY	789	124	15.7
7	IK0YUO	670	104	15.5
8	LA6M	814	121	14.9
9	9A/AI6V	1,833	263	14.3
10	KD5QHV	557	79	14.2

2016--2025 SSB -- Most Reverse Busts
Position	Call	QSOs	Reverse Busts	% Reverse Busts
1	DF0HQ	89,150	2,721	3.1
2	CN3A	98,729	1,427	1.4
3	JA3YBK	34,934	1,221	3.5
4	K3LR	70,598	1,111	1.6
5	F6KOP	30,766	1,079	3.5
6	TM3R	24,257	1,049	4.3
7	RU1A	55,456	1,047	1.9
8	YT5A	78,252	1,001	1.3
9	EA8RM	35,727	955	2.7
10	CA3CLF	982	915	93.2

2016--2025 CW -- Most Reverse Busts
Position	Call	QSOs	Reverse Busts	% Reverse Busts
1	DF0HQ	80,430	2,484	3.1
2	ES9C	73,518	2,326	3.2
3	RM9A	75,589	1,871	2.5
4	JS3CTQ	19,239	1,861	9.7
5	HG7T	69,063	1,751	2.5
6	YT5A	92,617	1,610	1.7
7	UA4M	69,767	1,552	2.2
8	HG6N	51,474	1,491	2.9
9	M6T	96,972	1,479	1.5
10	K3LR	71,706	1,463	2.0

2016--2025 SSB -- Highest Percentage of Reverse Busts (≥500 QSOs)
Position	Call	QSOs	% Reverse Busts
1	CA3CLF	982	93.2
2	PT4Z	1,011	20.3
3	BI3AO	524	12.2
4	DX3EVM	847	12.2
5	OG60F	4,258	11.4
6	BH8GFN	1,625	11.4
7	HB2Y	834	11.3
8	XE1ADY	1,197	10.9
9	BH7PCT	846	10.9
10	YY4RDC	509	10.6

2016--2025 CW -- Highest Percentage of Reverse Busts (≥500 QSOs)
Position	Call	QSOs	% Reverse Busts
1	R2VM	1,426	100.0
2	UT3NK	528	100.0
3	PE75W	1,408	29.3
4	OG55W	1,605	23.2
5	TA1C/2	1,513	18.1
6	DP65HSC	516	16.9
7	UX8IA	1,375	14.2
8	EB7A	6,198	13.1
9	LX75V	1,348	12.8
10	K3HW	3,645	11.7