Background:
Anecdotal evidence from resto shaman in [Resto] Healing Equivalency Points and other related threads has indicated that many resto shaman have sufficient longevity from gear and replenishment alone. My experiences are similar, and I chose to substitute Glyph of Water Mastery for Glyph of Healing Wave. However, the glyph doesn't behave quite like I expected, and I wanted to gather data to determine exactly what the mechanics behind it are. In the process, I discovered some unexpected behavior in both the glyph and Ancestral Awakening that I wanted to share with the community.

I have attached the combat log so that anyone who would like to verify my results can do so at their leisure.


Abbreviations:
GoHW = Glyph of Healing Wave
AA = Ancestral Awakening
AH = Ancestral Healing
EH = Effective Heal

Main Conclusions:
1.) GoHW's heal is based on HW's effective healing.
2.) Unlike AA, GoHW can crit indepently of HW.
3.) GoHW and AA heal for 22% and 33% respectively because they count purification twice.
4.) GoHW crits do not proc AH or AA.
5.) GoHW will consistently heal after HW but before any AA procs.

Methodology:
As GoHW is based off effective healing, I asked a shadow priest from my guild to help me test in Shattrath by taking repeated falling damage; this was the quickest and easiest way I could think of to do a controlled test without being interrupted.
1.) The shadow priest flew straight up and dismounted, taking approximately 10k falling damage.
2.) I cast 1-2 healing waves (depending on overheal from the first heal) to take her to full life.
3.) We repeated this process for 15 minutes worth of heals and I used WowCardioRaid to parse the resulting combat log.

Data Summary:
Total HW heals: 72
(Non-crit: 38)
(Crit: 34)

Total GoHW heals: 72
(Non-crit: 55)
(Crit: 17)

Total AA Heals: 34, all off HW crits.

This is where the data starts to get interesting. Unlike the tooltips state, both GoHW and AA actually heal for 22% and 33% of the original heal, respectively. Here is a sampling of my data for each crit healing wave, followed by the resulting GoHW and AA procs, respectively:
My working theory was that both GoHW and AA were double-dipping from purifcation, much like Deep Wounds had been double-dipping from enrage before it got hotfixed several weeks ago. To test this, I respecced so that I had 0/5 purification and 3/3 AA and cast a couple healing waves on myself. Sure enough, AA was healing for the tooltip amount of 30% of my effective healing.

Notes:
1.) As I was at full health the entire time and crits always brought my target to full health, all GoHW and AA heals were 100% overheal and as such are reported as raw values; for the purposes of this test, I was interested in theoretical data rather than in doing a cost-benefit analysis of the glyph itself.
2.) %HW refers to the value of the GoHW or AA heal expressed as a percentage of the original HW.
3.) Time refers to the amount of time in seconds after the original HW that the GoHW and AA heals landed according to my combat log. Both these times are in reference to the original HW - a time of +0.62s means that the heal occurred 0.61s after the HW.
4.) As I generally run with around 400 ms latency, my results for exact timing are somewhat volatile, but the overall trend is still very clear.

Conclusions:
1.) GoHW + AA are both affected twice by purification -- once for the original heal, and once for the glyph/talent itself, causing heals of 22% and 33% respectively. This is almost certainly unintended behavior.
2.) Additionally, GoHW double-dips on crits. A crit HW results in a potentially higher effective heal, and GoHW can itself crit. As shown above, a crit GoHW heals the exact same amount as an AA proc.
3.) Oddly enough, despite the above, GoHW is incapable of proccing Ancestral Healing on the shaman. This inconsistency is puzzling.
4.) The GoHW heal always takes place before the AA heal.
5.) These conclusions show that both AA and GoHW are slightly more effective than we would deduce from their tooltips. The difference is probably not enough to convince people to choose these talents/glyphs if they wouldn't already, but those who enjoy spreadsheets might wish to take note.

To do/Needs confirmation:
1.) Is it possible for GoHW to heal snipe AA in the same way that a crit heal followed by riptide does, or does it cause the AA to pick a different target? This requires real-world testing.
2.) Does GoHW use the Shaman's crit rate? (This requires a larger sample than I took.)
3.) Does GoHW eat up Tidal Force charges? (Preliminary testing seems to say no.)

AA and GoHW can be awesome in some raid situations. Here is a wws of Razuvious where I used HW all the fight :
Wow Web Stats

It seems that GoHW doesn't use my crit rate. In fact, it seems it doesn't take into account my crit talents (14% difference between my HW crit rate and my GoHW crit rate). Perhaps just a coincidence thus.

AA never healed me. But as I received regular healing thanks to GoHW, maybe I was never the target with lowest HP.

Hope that will help you.

(Sorry for poor english, I'm french)

Thank you Philondra. This thread is very helpful. I look forward to more "needs confirmation" results.

Zah--your English is better than many native speakers! lol. Thank you for your results. Perhaps they will fix GoHW like they did Earth shield to reflect our true crit rate.

On a side note, could you explain to the mathematically challenged (aka me lol) how AA and GoHW count purification twice? It seems to me that 10% of 20 is 2 and of 30 it is 3, so wouldn't that translate to 22% and 33%? Again, I'm an english major and I don't do math, so I'm probably mistaken. Thanks!

Good question. The talents double-dip because the 10% bonus from Purification is accounted for in the initial spell: (Healing Wave + 10%) * 30%. So when the Glyph or AA bonus gets +10%, that bonus has effectively been applied twice: (HW + 10%) * 30% * 10%. See?

Great post. I'll have to update my spreadsheet. I'm surprised by the lack of AF proc I would assume that GoHW does proc riptide though?

The glyph heal doesn't proc anything. It's only interesting feature is that it can crit independently of the initial heal.

A similar glyph heal for Paladins (glyph of Holy Light, heals for 10% of HL within 8 yards), does not have the same crit rate as HL, since it is a Nature spell (Paladins get 5% crit to just Holy spells).

GoHW is from the physical school, so it sounds like no 5% crit from talents and it uses melee crit rate.

I've looked through some WWS parses this morning and I've seen differences from -24% crit to +3% crit on GoHW compared to HW. I am nowhere near comfortable with the data I've seen so far on this. A few of those were anonymous reports, so I couldn't check talent builds to correlate crit talents, etc. Assumptions around talents are a bit unfounded at this point, but it would be nice to see that data.

For those of you who have used the Glyph extensively, could you provide us with data/parses so we can build a reliable sampling?

Thanks for the data. Did you test it with Healing Way?

AA/GoHW effectively boosts our crit from 50% increase to 133% increase. (50% + 1.5 * 22% + 1.5 * 33%)

Looking just at the raw healing, it is edging past Chain Heal (4 targets). Too bad there are not enough encounters to make HW/GoHW viable more often. I loved it when running Heroics.

I generally take 3/3 Healing Way in my builds, and although I did not record data for GoHW without 3/3 Hway, I see no reason to believe that GoHW would double dip. However, GoHW is increased by the fact that HW heals for more on targets with Hway.

The log I linked in the original post contains data points that both do and do not include HWay on the target, and the numbers for each are consistent with my findings.

As grayshock pointed out, with the exception of its ability to crit, as far as I can tell GoHW behaves exactly like AA. It doesn't proc earthliving, AH, or its own independent AA proc. I don't have enough data points to conclude with 100% certainty that it doesn't proc trinkets, and given that GoHW procs between .2-.5s after HW, it would be impossible for me to accurately test this given that my latency would introduce a large margin of error. That said, during testing I had both Jet'ze's Bell and Forethought Talisman equipped but didn't notice any procs that would suggest GoHW triggers trinkets. GoHW only procs when HW targets someone else, so any forethought talisman procs on myself would imply that they were triggered by GoHW.

I am away this weekend but will try to get more data points on Monday to see if I can nail down what affects GoHW's crit rate. For the time being, here is a WWS report of a full Naxx-10 clear that shows me having a 39% crit rate with HW and only 32% crit rate with GoHW:

Wow Web Stats

I logged a partial Naxx-10 raid that my guild did last night after we finished up our 25 mans. I have logged out in similar gear to that which I was using last night -- the only difference is that I was using Darkmoon Card: Greatness instead of Forethought Talisman, as I was the sole healer and wanted more longevity. Here is the log:

Wow Web Stats

If I combined these numbers with my other log (same talents; slightly different gear) the numbers work out as such:

HW: 462 casts (166 crits) = 36.36% crit
GoHW: 400 procs (118 crits) = 29.5% crit

My "real world" data seem to show a difference of ~7% in crit rate, but I need a lot more data in order to make an accurate conclusion. If any members of the community have parses with GoHW, please PM me your WWS/Stasis link (and a link to your talent build, just in case) so that I can try to isolate exactly what does and doesn't affect GoHW.