Thanks for all the excellent feedback... I'll try to answer as best I can, forgive me if I miss something, I'm running between work, teaching and taking classes this week!
1. Causality - this survey cannot establish causality for anything, since it is a point in time study. In order to establish the causes of correlation we would need to execute longitudinal studies using very tightly controlled / prescribed methods of (say) packing, erecting tarps under monitored (and therefore comparable) weather conditions. This is way beyond what I can handle off the side of my desk, but would definitely be worth while to establish the REASONS for these correlations, and even to confirm that these correlations exist!
2. Sample sizes - the total respondent base for this survey was 121 tarp users. Only one person put in more than one tarp, so this is 120 different people. While this is a decent (if not extensive) sample size at the 90% confidence level, individual cells within the study are far below statistical confidence level. This is why I called this a non-scientific study. What this DOES do is establish a basis to create a series of hypotheses which could be tested by other, deeper studies over time.
3. Stuffing vs rolling/folding - I too was surprised at the advice given on the BPL course re stuffing the tarp in the bottom of the pack, underneath the pack liner, but it actually is a good way to pack, allows you to shape your pack and prevents excessive folding or creasing of the tarp. If there was a deeper rationale than that, I don't know what it was (perhaps Mike C! could jump in on this!?). My observation / guess on the risk of rolling/folding is that this then creates a "solid" inside your pack, which is more prone to puncture from tent stakes, spork, etc, whereas a loosely stuffed (not stuff sacked) tarp might flex more and not puncture so easily. Since Mike C!'s advice is that your pack should be completely empty each night (and usable as part of your sleep system), and completely repacked each morning, you have the ability to carefully repack vs stuff the tarp in AROUND other things in your pack. Perhaps when you take a systems view, it makes more sense.
4. Tent stakes - I use a small MYOG nylon bag (made specifically for my stakes) to protect my fragile things from my stakes, and I slide it into what's left of the back pad space in my Jam 2 (along with my folded z-lite). This protect other things from my stakes, and means I can easily find them when I need them.
5. Next Steps - I plan to take this study, plus the feedback I have received and put together a set of hypotheses and a test plan for each hypothesis. I'd like to publish the study here and see if folks are up for turning it into a longitudinal study, with all that would entail (specific tests and documentation collected on trail while volunteers are outdoors with their tarps). In addition, perhaps BPL would be willing to sponsor a process for all of us to LOG tarp, hammock AND tent damage AS IT OCCURS, so that we can build a long term database of durability of our shelter systems. I think this is the only way to really establish best practice around these things.
Post if you are in support of this / willing to volunteer some time to complete documentation following a few backpacking trips over the next year or so, and I'll directly approach Ryan in a few weeks once I have the hypotheses established. It would also be great if one of the scientists on the form (Rog C????) would be willing to act as peer reviewer / advisor over time. Would love our comments on this?
6 - Perhaps in parallel with the data analysis which I am willing to pull together over time, there needs to be a gear destruction test or something like that, to test the resilience of construction methods/materials IN THE LAB. I cannot do that type of testing, but would LOVE to collaborate with someone who can. Please, if you are interested in collaborating on that - PM me!
7 - You will note that I did not publish any of the information about the different manufacturers, couple of reasons for that - primarily, this was not a supportable scientific study, so didn't want to bad mouth anyone, and secondarily, it wasn't an apples to oranges comparison. I think it would be great to do comparative studies on this, but that would need much deeper and more controlled samples.
Anyway, gotta head out now... but, once again, thanks for your feedback on this... keep it coming, as it will form a strong basis for the hypotheses needed for the next phase of this work.
Cheers and happy trails!