I am not going to out any of the networks I involved in this study but I was actually pretty shocked when I tested the same offer over 5 networks and the results were a bit scary, cos it could mean that you do have a profitable campaign only the offer is letting you down.
I tested an offer over 4 networks and sent 200 clicks to each. here are the results
Network 1
Payout was 5.50
with 200 clicks I got 11 leads with an epc of 30 cents
Network 2
Payout was 5.15
With 200 clicks I got 14 leads with an epc of 36 cents
Network 3
Payout was 5.25
With 200 clicks I got 7 leads with an epc of 18 cents
Network 4
Payout was 5.05
With 200 clicks I got 27 leads with an epc 68 cents
Well as you can see, network 4 was the heavy hitter and I have no fucking clue to why it converted so so much better then the other networks.
And what was more twisted was this network, the reason why I am not naming networks is always sledged at having bad tracking and that the offers dont convert anywhere as good, and the second lowest epc was a network that's known for having superb tracking??
Well I can tell you it PAYS to TEST on DIFFERENT networks, so I know AM's we all get loyal to them and they are great friends, but if your holding back a campaign because of loyalty remember this is your job and they have 100's of others affs making them money too.
But in the end of the day, TEST DIFFERENT NETWORKS for the same offer as I just turned a slightly losing campaign into a 100% roi campaign.

Great tip Maynzie. Do you mind mentioning which vertical you used?
I starting to test the same offers with different networks for this very reason. But for now I'll keep it to about three until I can ramp up my volume again in order to get weekly payments asap lol 
Although I generally agree with your point... that's a pretty low number of conversions to make a conclusive argument.
Yah I do agree man, but I have done quite a lot of volume to network 4 (over 6000 leads at 13.95% conversion rates) and in the past 2 months I have tested a network 1 and 3 for around 900 clicks each letting it run for 1-2 days and they had a conversion rate of 4-6% looking back at the stats now. I posted the shorter case study that I ran yesterday to demonstrate to the forum the difference between the offers, and for most beginners they cut off a campaign without profits in a single day, but as you can see depending on what network you ran with, would determine whether you ran the campaign or not.
so yeah might not be the best information for the seasoned pro, but it could make or break the motivation for an up and coming marketer
great post man.
it would be interesting to see a comparison of load speed / number of redirects for each of the offer links for each network.
Great advice, I've also had EPCs practically double just by testing different networks. I've even had some offers that I had a paybump on lose to another network that didn't have a bump yet. Some offers will shave different networks at different times so that could be one cause.
Another thing to remember is to try and split your traffic and test them at the same time, Sunday might be that offers strongest day so if your first network gets Sunday and second network gets Monday then you wont have complete accuracy and could lose out on some money.
Are you reading the EPCs reported to you by your tracking solution or the EPCs reported to you by the network? I too won't name networks, but some networks manipulate their inbound clicks, so if you're looking at the EPC on the network, it'll artificially be higher than it really is.
All this is a great point. There are so many factors in things. Always remember that you're in with a bunch of other affiliates on an offer. If the other affiliates traffic sucks then there's a chance that maybe the advertiser is shaving to compensate for it and you're being penalized for something else someone else is fucking up. Also as someone mentioned, network load times are important that's a HUGE piece of the puzzle.
One thing I can say is split between networks then if you have a network you particularly like, and they're not the winning network, just communicate with them the situation and see if they can get to the bottom of it.
P.S. one other thing when you do these comparisons make sure you're not using the click count from the network. There's a handful of networks around that shave clicks to make epc's look better when in reality they're the same. Make sure you're using your clicks from your own tracking to calculate EPC. But yes always split test 
thing is, why should you bother going that road?
When you do not test it you will never find out (so you never complain and just stop the campaign).
When you DO find out about it by running it on different networks and get statistical relevant data and see that one is better, i would not go back and ask the other network(s) why it is like that. For me there is only the money difference and it might be true thats not the Networks fault in general but the Advertisers that are running the offer but then again ... for me its still just the monney difference.
Would be super awesome when networks would tell you right away "oh okay we drop like 50% of the conversions atm because our Affiliates are doing shit" then you can show quality traffic and get different payout or w/e. But as it is atm neither the networks have full clue nor does those that are running the offer ...
Makes it quite a bad thing :/
well i would not leave the network because of that and would definatly run there stuff again. Its not like i would "blacklist" networks after stuff like that just talking strictly on a offer base 
But yeah the pixel thingy is a thing to consider even though when i think about it the network should have that in mind all the time and test it or something (working for a big merchant in my country and we run pixels aswell and i have to check them every day and make sure they are working etc ...)
Nice Thread!!!
I never do that....test just the networks. Idiot!
I love this forum. I learn every day here 
I've been helping an affiliate out recently and he said he couldn't get the campaign to work, so I told him to split across a few networks with the same offer, so he tested out 3 networks and 1 of them converted triple the amount of the lowest performer and 1.5x the second performer, this took a campaign from the negatives into the positives.
Can't stress enough how important this is to make sure you do split across networks, especially if you're running volume.
+ In the original post I forgot to mention and it was stated in this thread, always go by total revenue over epc, some networks don't report double clicks or even yet shave clicks, so epc's aren't always truthful. Better comparing the revenues
Nice tip, can definitely make or break campaigns. If the network has lower EPC's, it might not be them scrubbing you.
Sometimes the advertiser will scrub the network as a whole to make up for bad leads or whatever.
Just went back and read this again. One thing you want to make sure of is that you're getting enough data to be relevant. 200 clicks is pretty low.
You can use this calculator to make sure that your data is significant enough to matter.
http://www.splittester.com/index.php
But that's when you are driving a lot of volume, right?
I mean, if it is only a few clicks a day, like 20, it's pointless to split test traffic between networks.. to gain statistically significant data, you'd need a lot of clicks.
I know this is bumping an old post, but the day I did what OP suggested (last december), is the day I started 'getting it' and making profit.
I was basically drinking the kool aid of some self claimed affiliate marketing magnate; one he feeds to his members on his paid forum and believed all of what he said - that his network is the best out there, and no other network comes close! It was a real LOL, and OMG moment when I split tested same offer on that network with CD & MUNDO and both kicked their ass cvr wise.
2 Lessons learned
1) Don't trust what people say, just because...
2) Always split test networks every single time