Recent revelations one One Power strength have created questions as to the relative strength in the Power of certain characters. Although we had a debate on this last week, I've had some time to go research the topic and gather my ideas on the topic.

How strong is Nynaeve compared to her friends, and how strong are they compared to Cadsuane, the strongest woman in the Tower?

Nynaeve

It's always been difficult to put a value on Nynaeve's strength, especially because she's been growing in power, had a block for a large part of the series, and is generally self-effacing. We've also had examples of channelers who are definitely stronger than her, in the form of Alivia and Sharina.

What's clear from Brandon's answers on Nynaeve is that is close to as strong as is possible in saidar. There are only six women who are of greater strength, and although this may span more than one level above her, she is very high up indeed. RJ pretty much equated the highest male and female in power, and therefore Lanfear is comparable to Lews Therin to some degree, if not exactly. For this reason, it's fair to extrapolate that Nynaeve is not too much weaker than Rand in the Power. IMO she's not too close to him either. Alivia is said to be considerably stronger than Nynaeve in strength in WH. Furthermore, Lanfear in a weakened state in the form of Cyndane still exceeds Graendal in strength, and that is a strong pointer to the fact that some greater levels do exist above Nynaeve, if Graendal was indeed one of the stronger women among the Forsaken. We also know from WH (Ideas of Importance) that the Seafolk made a circle of six to beat Nynaeve down if her anger got the better of her after they humiliated her. It's a strong parallel to six women's inability to overwhelm Rand, showing that he's that extra step higher. We also know that two failed against Nynaeve, and that Liandrin thought three could take on Moghedien.

For this reason, Nynaeve is probably 80-90% as strong as Rand - say 85%. You'd probably find Lanfear close to Rand, or slightly weaker, Cyndane at 95%, and Graendal at 90%, with Semirhage and Mesaana at 80-85%.

Egwene, Elayne, Aviendha

I've always believed that they were much weaker than Nynaeve in strength. According to RJ, they are a level below Nynaeve. I'd estimate their power to be about half that of Rand's, or 50%.

Compared to Nynaeve we have the following quotes...

TFOH (Ripped Away) - The amount of saidar that Nynaeve had drawn into herself was amazing.

TSR (Playing with Fire) - With so many exclaiming over their strength – everyone said she and Elayne would be among the strongest Aes Sedai, if not the strongest, in a thousand years or more – she had just assumed they were as strong as he. Near to it, at least. She had just been rudely disabused. Perhaps Nynaeve could come close if she was angry enough…

TGH (Summoned) - … Nynaeve was the Wisdom in their village … Once she gains conscious control of what she does without knowing, she will be as strong as any in Tar Valon. With training, she will shine like a bonfire beside the candles of Egwene and Elayne.

The first quote shows Elayne's surprise at Nynaeve's strength. The second is Egwene's fear of Rand's strength and her thoughts that maybe Nynaeve could match him - which is a clear indicator that Nynaeve is much stronger than Elayne/Egwene. Moiraine's opinion in the last quote is also very specific.

Later in the series Egwene states... ACoS (The Figurehead) - Moghedien has a good reason to dislike her, very personally, and the only sister who could match one of the Forsaken alone, when she could channel at all, was in Ebou Dar. Moghedien could have killed Egwene without anyone noticing …

We also know from Moghedien in ACoS (Mindtrap), that Moghedien was considered to be too weak to be noticed by very strong opponents in the War of Power, until she killed them. This is more than confirmed by Nynaeve's ability to match her in strength as early as TSR, and Egwene's own personal opinion on her relative strength to Moghedien's. We also know from Graendal that Cyndane is 'so much stronger' than Moghedien.

Detractors of Nynaeve's strength refer to her inability to shield Elayne in ACoS (Swoven Night). However, I consider this to be a failure of evidence on many levels...
- Nynaeve has shielded much stronger opponents while they held their maximum.
- Nynaeve lashed out with a reflex and wasn't concentrating.
- The chance that Elayne was holding all her potential at that stage to weave an illusion is not high, which is proof of Nynaeve's massive failure rather than her inability to do this task.

In TFoH, Egwene told Rand that he is probably stronger than she and Aviendha combined, although none of the channelers had reached their potential, it shows that Egwene's strength is not neglible compared to Rand's, if she combines it with her friend. In KoD Egwene estimates that she could overcome five Sisters who were not holding the Power, but once they did hold it, she would have no chance.

Cadsuane

Cadsuane is the strongest Sister in the Tower. However, her strength probably isn't all that great. Initially it seems that she is very strong, with an introductory quote of...

ACoS (Diamonds and Stars) - Once Cadsuane Melaidhrin had been the standard by which every new entry into the novice books was judged. Until Elayne Trakand, none had come to the White Tower in her lifetime who could match that standard, much less surpass it…”

and...

NS (An Arrival) - A number of women were stronger than she [Moiraine], but only one [Cadsuane] could be as much stronger as this one… “Meilyn is considerably older. When she and I are gone, that leaves Kerene the strongest… From Kerene, it’s a sharp drop to the next five. Five once this child and the Sanche girl reach their potential.”

However, it seems that this sharp drop from Kerene to Moiraine isn't too great...

ACoS (Diamonds and Stars) - The woman did not stand that far above her [Merana]. Not really. Just higher than any other sister.

We also know from the cleansing of saidin that Cadsuane was drawing more saidar than Elza and Merise combined, and this made Elza believe that Cadsuane was using an angreal, which she was. This indicates that Cadsuane is probably weaker than two combined Aes Sedai. In contrast, we have a quote from Aviendha in TFOH which already states that Egwene is strong enough in saidar to overwhelm both Amys and Melaine together. Amys is as strong as Moiraine in one quote and as strong as Sheriam in another. Melaine has less strength. This already implies that Egwene is very much stronger than Cadsuane. Once again, I don't believe that Cadsuane's strength is greater than 30 compared to Egwene/Elayne's strength of 45.

I haven't included everything because I think it can be added if debates do occur, but overall, my strength tree for these females is...

- Nynaeve - 85 (percent of maximum, al'Thor at 100)
- Egwene/Elayne - 50
- Cadsuane - 30

Other numbers...
- Lanfear - 95 - 100
- Cyndane - 95
- Graendal - 90
- Semirhage - 80
- Mesaana - 75
- Moghedien - 60
- Bode - 45
- Moiraine - 25
- Aes Sedai - 15-25