And of course, the best way to have this discussion is when it is based upon a statistically significant set of information that we can all populate and refer to.

Did it clear?

Pretty sure that there's a contingent of folks who won't consider the data on DidItClear "statistically significant" until it captures every single flight for every single passenger on all of UA

A reverse auction is a situation where multiple sellers compete for a buyer.

technically, a "forward auction" is one in which a single item's price goes up with bids, a "reverse auction" is one where the price to provide the item (usually a bid for work, or procurement) is driven downward by extra bids.

You are correct that a technical sense, it is usually said that any auction would require multiple bidders, and if we want to be even more technical, nothing about what UA is doing is what we think of as an English Auction in that it is not open with others knowing the bids.

I have used the term to describe UA lowering the price it offers the upsell at over time, in essence bidding against itself. I think its probably the closest common term to what UA is doing. If you know of a better closer term, would love to know it.

To be fair, with self-reporting from FTers, there's going to be a selection bias present in the data regardless of how large the data set is--unless as you say it covered all pax and flights.

No doubt about that. What bothers me, though, is that some people apparently come to the table with the notion that selection bias = completely unusable results.

The key is to think critically about the selection bias and what it's likely to do to the data. Take brain imaging studies, for example. Most subjects in those studies are 18-26 year old smart people. (I'll let you figure out why.) That's some pretty big selection bias. And yet, we accept it and move on, because the bias should have no predicted effect on the research questions being studied. To the extent that there are concerns, these are noted and recognized as limitations of the study.

My hope is that people here can move beyond their initial skepticism and accept the data on DidItClear while recognizing that the limitations on the data are themselves limited.

The same bias is, of course, present here in FT reporting in this thread...

UDU stats and now did it clear at least capture the information in a somewhat organized fashion.

But yes, any self reporting system will have bias.

Yield management?

Sale?

Discounting something that has not been bought at a higher price is not a reverse auction.

Since it is a fact that United has increased the sale of paid premium upgrades, and since it is a fact that they haven't ripped out E seats and added more BF/GF seats, isn't it an unassailable conclusion that elites have less CPU upgrades, and face increased competition for instrument supported upgrades?

Yes, of course. If you think I'm disputing that you haven't been paying attention

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 6_1_3 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10B329 Safari/8536.25)

6/20 booked for May 4th flight. T-72 window came and nobody upgraded. My window opened yesterday. R9

So, isn't the entire premise of this thread invalid?

Perhaps. CPUs are certainly not non-existent though like some would have us believe. Plenty of grey in between the black and white

Its strange that Star does not see the clear trend in continuously lowering the buy up offers For example on recent DEN-SFO trip Sat-Mon. At booking got the offer immediately for $400+, also offered when looking at my res and on OLCI offer lowered $239. I was #1 of 20 for the CPU and sat E+ because it wasn't worth it. United wants to sell upgrades/E+ any way they can. With few caring to pay for a poor product, the price drops. This is clearly the United revenue enhancement strategy.

This strategy has not totally affected my upgrade rate as I have planned pretty well. I have cleared 2 of 4 eligible CPU flights, successfully applied 2 RPUs and bought into discounted Z on a midcons. I recently bought a TOD for an upcoming west coast trip because I was tired of watching and worrying about it. The effort and $ is losing my loyalty. I'll go from $35K and 100K miles last year to $10K and 50K miles this year on UA. I will occasionally fly UA when convenient for me, but my international travel requires a connection, why not travel with a company that tries to take care of its elites (AA)? This doesn't even get into the overall poor customer experience on United.

On AA I am 8 for 8 UDU and 3 of 4 on SWUs. Even if AA service levels go down, could they sink below how United treats me? I'm willing to bet DP will not sink as low as Mr Smi$ek.

There is a major bias, but its not a selection bias, which refers to bias in the subjects that are chosen by a studies authors. Here that has not been done as no sample was selected or pulled by the authors.

What there is a "self-selecting bias" which refers to those participating selecting themselves. Polls done this way (like those great pop up polls on Fox news, etc "is Obama a communist") are called "SLOPs"

A good basic discussion of these type of studies (and their lack of statistical validity) is here: http://www.aapor.org/Content/aapor/R...es/default.htm

I post my own Data on DidItClear. I find the results interesting. I am glad that you (and others?) put the site together. I thank you for your work. But don't for a moment think that the results are statistically valid for any purpose, they are not. Once you rely upon people to select themselves you are no longer representative period. What you have is the results of those who felt strongly enough about their experiences to post. Its not a statistical sample at all. What you may have (and its interesting) is some information on when upgrades are most/least likely to clear, and at what cities. [This is assuming people input all of their data, not selected data ]. Again its interesting data, but there is not a sample, let alone a random sample, and you can't extrapolate from it under well established rules of statistics.

Frankly, the data that you would get from asking 10 random folks in Group 1/2 at the airport waiting to board a UA flight would be better (as you have at least pulled a sample, if not a random one). Likewise, I find the upgrade percentages that people post on FT to be interesting (note I posted my 2013 upgrade rates in this thread) but again it has a clear self selection bias to it.

Yup.

I appreciate the suggestions, but I don't think that any of these things capture the essence of what I was describing as well, and I think people understood what I was saying/getting at.