Probability of Winning A Grand Canyon Permit
I was curious if anyone, had an updated rendition of the graph linked below?
https://rrfw.org/RaftingGrandCanyon/File:Gc_stats_2011_Delagarza.png
A better under standing of month to month permit probability would be helpful. I understand that it is easer to get a permit in the winter compared to the fall and spring months. But graphed data built from lottery stats from 2010-2016 would be helpful.
https://rrfw.org/RaftingGrandCanyon/File:Gc_stats_2011_Delagarza.png
A better under standing of month to month permit probability would be helpful. I understand that it is easer to get a permit in the winter compared to the fall and spring months. But graphed data built from lottery stats from 2010-2016 would be helpful.
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Keep in mind that that graph is plotted on a logarithmic scale, so, all those lines that look like they're way up by 100% are really somewhere between 10 and 100. The 50% line should probably be between 2/3 and 3/4 of the way from 10 to 100, so the bulk of those lines are probably around 50%.
Nonetheless, much better odds in winter. . .
I'll call the creator of that- not sure how much he's on the buzz, and see if he'll post up another one.
Cheers
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Lol. Wouldn't matter if you did at this point. You would have had to have your $200-$400 deposit in by today at noon. None of my family got a follow up, maybe next time.
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As it stands the statical data provided by the park is not as usable as it could be.
Are there any database engineer's out there that would like to work on a project improving that data?
In theory once configured appropriately in a data base queries could be designed which would show stats for winning a permit on a given date in the future based on data from the past.
That data could then be used to create a better graph. Thoughts?
Are there any database engineer's out there that would like to work on a project improving that data?
In theory once configured appropriately in a data base queries could be designed which would show stats for winning a permit on a given date in the future based on data from the past.
That data could then be used to create a better graph. Thoughts?
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The tricky part about that is that Sept. 4, for example, is a Tuesday some years, and a Saturday other years. The dates don't always follow through year after year. With shorter trips (high use season) it's more pronounced to see launches on Saturday, Sunday, and Monday more difficult to get because many people want to have only 2 weeks away from work, rather than parts of 3.
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Yeah, but it would still be better than what they've got now. And they manage to do it for the 4 Rivers permits. Should be possible for the GC, however with the government shrinkage that's going on, the person to do it probably retired and their position is vacant (like Logan suggests Kara Lamb's position may be on this thread).
Note: the data in the graph are from '07 - '11 lotteries, I'd be interested in knowing if it's changed any now that the legacy waitlist trip leaders have all worked out of the system, or seeing what the stats are since they're not influencing permit distributions.
-AH
That log scale graph is very course information.
I have used the numbers from the NPS site:
http://www.nps.gov/grca/planyourvisit/noncommercial-riv-docs.htm
Looking at the time of year that I want to launch I then adjust for day of the week in the historical data to smooth things out. There is a noticeable bias in which day of the week people bid for though that is seasonal too as mentioned earlier and not totally consistent year to year.
There doesn't seem to be any magic technique as a lot of people are doing the same analysis. My group got lucky this year for a fall launch... I take credit for my amazing statistical prowess but reality is that it is probably just luck.
I have used the numbers from the NPS site:
http://www.nps.gov/grca/planyourvisit/noncommercial-riv-docs.htm
Looking at the time of year that I want to launch I then adjust for day of the week in the historical data to smooth things out. There is a noticeable bias in which day of the week people bid for though that is seasonal too as mentioned earlier and not totally consistent year to year.
There doesn't seem to be any magic technique as a lot of people are doing the same analysis. My group got lucky this year for a fall launch... I take credit for my amazing statistical prowess but reality is that it is probably just luck.
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@ climbdenali - I agree with your thought of days of the week being a factor in your chances of winning.
Even without a computer program you could review the lottery stats from every Monday the first week of June from 2010-2015 and run those numbers.
You could then compare them with every Saturday within the first week of June in the same time range. That is actual, data.
A SQL application would make it possible run queries based on fields for a range of dates or days or months or years. The hard part is uploading the data and writing and testing the algorithms.
Even without a computer program you could review the lottery stats from every Monday the first week of June from 2010-2015 and run those numbers.
You could then compare them with every Saturday within the first week of June in the same time range. That is actual, data.
A SQL application would make it possible run queries based on fields for a range of dates or days or months or years. The hard part is uploading the data and writing and testing the algorithms.
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Good point that the data needs updating. I have asked Dave if he will do that. Andy, I can find nowhere that the waiting list folks are all gone. It appears the NPS expects to finish the list in another ten years. Meanwhile, I can book an entire commercial trip for next year and for 2017 at this time. Yes, day of the week matters, slightly, but I have lost every year since 2007 for a mid week mid January date. You may be lucky, but at least in a waiting list system, you were guaranteed a launch if you lived long enough. Now? No guarantees, except that you can charter an entire commercial trip. Will report back what Dave says. Yours as ever, Tom
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guarantees depends on points
@ Tom,
You could guarantee your self access to a trip if you apply to a set of dates with a group of folks with enough points to increases your chances at winning one of those dates:
Check out this attached image which shows the difference in probability of winning a permit based on a group of folks with 25 point vs a person with 1 point applying to 4 January dates and one March date from the last follow up lottery stats held 10.15.2015.
Group 97% chance
Individual 8% chance
The math is not in your favor as an individual with 1 point. As is such your choices are group points or commercial for guaranteed 2016 trip.
@ Tom,
You could guarantee your self access to a trip if you apply to a set of dates with a group of folks with enough points to increases your chances at winning one of those dates:
Check out this attached image which shows the difference in probability of winning a permit based on a group of folks with 25 point vs a person with 1 point applying to 4 January dates and one March date from the last follow up lottery stats held 10.15.2015.
Group 97% chance
Individual 8% chance
The math is not in your favor as an individual with 1 point. As is such your choices are group points or commercial for guaranteed 2016 trip.
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Tangent
Tom,
Perhaps, one modification to the existing system that would maintain equivalent private trip participants numbers (about 1800 people) in the winter season but also increase permit access would be to:
Allow only small trips (8 people) with 2 launches per day in the winter season and double the amount of permits available for that season.
According to the stats in the linked document:
http://www.nps.gov/grca/planyourvisit/upload/River_Stats_Oct_2014_Update.pdf
CMRP predicted an average non commercial per trip participants to be 15.46 people when in actuality it was 8.73 people in 2014. Thus, over the winter period most 16 person trips are a little over half full. That, is bad policy for increasing access to a static number of river runners.
Simple math is to offer more trips at the size closest to the average while maintaining user caps of about 1800 for the winter season.
Tom,
Perhaps, one modification to the existing system that would maintain equivalent private trip participants numbers (about 1800 people) in the winter season but also increase permit access would be to:
Allow only small trips (8 people) with 2 launches per day in the winter season and double the amount of permits available for that season.
According to the stats in the linked document:
http://www.nps.gov/grca/planyourvisit/upload/River_Stats_Oct_2014_Update.pdf
CMRP predicted an average non commercial per trip participants to be 15.46 people when in actuality it was 8.73 people in 2014. Thus, over the winter period most 16 person trips are a little over half full. That, is bad policy for increasing access to a static number of river runners.
Simple math is to offer more trips at the size closest to the average while maintaining user caps of about 1800 for the winter season.
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Hi Buckman, you have an interesting idea. For years we have been writing the NPS saying the NPS forecast a huge use in the winter, and the actual number of people is half that. I have suggested year after year decreasing the hurdles in the winter, like decreasing the fees and or eliminating the one trip a year rule and or returning the winter trip lenght to Diamand to 30 days. I had not thought of doubling the winter launches and halving the group size. It would mean twice the winter trip contacts.
As to stacking the lottery, one could try that, and i know folks who do. Without going into a lot of math, when 1259 applications try for 10 trips, as happened 6 days ago, I "think" my chances are not so good...
All the best, tom
As to stacking the lottery, one could try that, and i know folks who do. Without going into a lot of math, when 1259 applications try for 10 trips, as happened 6 days ago, I "think" my chances are not so good...
All the best, tom
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1. Twice the contact with the same number of people. This would not be different from the summer season right? I think there are two launch's per day at during that season as well.
2. We also assume that such a change would fill or help increase total winter trip numbers to the 1800 per season allotment. I think they would go up but we have no data to suggest they would under a new model. They could very well remain the same or go up slightly or go down.
3. Such an change would increase access though.
4. Tom I think we share the same views on most all of this information. Thanks for you advocacy.
2. We also assume that such a change would fill or help increase total winter trip numbers to the 1800 per season allotment. I think they would go up but we have no data to suggest they would under a new model. They could very well remain the same or go up slightly or go down.
3. Such an change would increase access though.
4. Tom I think we share the same views on most all of this information. Thanks for you advocacy.
Hi Buckman,
The concept is sound, and the only grumbling you would get could be from the folks who want to take more than eight in their party. But a small launch option every other day could be a workable compromise.
The big thing I see is that your idea would run up against the limitation on total launches that the CRMP establishes. The Park holds that in essentially immutable status. Not sure how to maneuver around that and get the additional access. I know at least one argument to be made, but this likely would not fall within their "adaptive management" parameters.
There probably also would be some environmental concerns, most surely over doubling the number of parties competing for firewood, and the (modest) lessening in trip solitude. But the CRMP launch ceiling would be a huge obstacle to overcome.
FWIW.
Rich Phillips
The concept is sound, and the only grumbling you would get could be from the folks who want to take more than eight in their party. But a small launch option every other day could be a workable compromise.
The big thing I see is that your idea would run up against the limitation on total launches that the CRMP establishes. The Park holds that in essentially immutable status. Not sure how to maneuver around that and get the additional access. I know at least one argument to be made, but this likely would not fall within their "adaptive management" parameters.
There probably also would be some environmental concerns, most surely over doubling the number of parties competing for firewood, and the (modest) lessening in trip solitude. But the CRMP launch ceiling would be a huge obstacle to overcome.
FWIW.
Rich Phillips
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Dugger,
Check out the document linked below:
http://www.nps.gov/grca/planyourvisit/upload/River_and_Weighted_Lottery_FAQs.pdf
The short answer to your question is that you have a group of folks apply for the same 5 launch dates within a given lottery. This group has an agreement to allow each other on a single permit should someone within the group win one a permit.
Example: 16 people apply for June, 1-5 launch dates in a lottery. One of those people wins a perming and invites the other 15 applications on his/her permit.
Hope that helps.
Check out the document linked below:
http://www.nps.gov/grca/planyourvisit/upload/River_and_Weighted_Lottery_FAQs.pdf
The short answer to your question is that you have a group of folks apply for the same 5 launch dates within a given lottery. This group has an agreement to allow each other on a single permit should someone within the group win one a permit.
Example: 16 people apply for June, 1-5 launch dates in a lottery. One of those people wins a perming and invites the other 15 applications on his/her permit.
Hope that helps.
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Richp,
1. I agree, with the workable compromise.
2. I agree, the park would be slow to change this policy for a verity of reasons based on their history of slow change.
3. That said, and increase total launch's that is proportional to a preceding population limit for a given time frame does not in it self equal higher environmental impact.
Example: A large 16in diamater pizza does not get bigger when the more slices you cut into it. It stays the same size.
Why then would total allowed winter launch's be immutable?
1. I agree, with the workable compromise.
2. I agree, the park would be slow to change this policy for a verity of reasons based on their history of slow change.
3. That said, and increase total launch's that is proportional to a preceding population limit for a given time frame does not in it self equal higher environmental impact.
Example: A large 16in diamater pizza does not get bigger when the more slices you cut into it. It stays the same size.
Why then would total allowed winter launch's be immutable?
Hi Buckman,
I pretty much agree. But over the years, I sat in a lot of meetings with Park representatives back when I was on the GCPBA Board. The first and foremost perspective they have is launches, not so much user-days. They emphasize that the CRMP is a launch-based system, and that the CRMP is pretty much a closed document (aside from minor adjustments they make through what they call "adaptive management"). To the Park, lapsed ideal user-day totals are not as critical as trying to approach 100% use of all launches.
So in that context, the "let's try to get to 1,800 participants each year in the winter" argument we would make isn't as weighty. Yes, it's important to folks like us to optimize access. But in the CRMP launch context, the Park already is getting 95+% of all the scheduled launches out, and objectively that's not bad. It seems less important to them that the user-days are not similarly optimized.
As to pizzas, take that pizza and cut it in half and put each half at a separate table that requires separate linen goods, wait staff, bussing, etc. (Yeah, I know that's sort of feeble, but it's the best I can do.) In this case, the Park might argue that if you have two 8-person groups each competing for firewood, that's twice the environmental impact of one 16-person group. It's also twice the load on the beaches, since the campsite use would be doubled. This all gets evaluated in the general category, "the winter is a time when the Canyon can get a little rest."
It's not the total allowed winter launches that is immutable, it's the total number for the entire year -- 504, IIRC. They consider that number (embodied in the CRMP) just about untouchable. So absent a new CRMP, the only way they could see to add launches in the winter is to chop them in some other season.
Now I don't see it quite that way. I would argue that (notwithstanding the fact it's a launch based system) the winter component of the 504 launches was developed from some user-day use projection in the vicinity of 16 persons per trip times some arbitrary trip length. Since we now know that actual use is far less, my view is that your idea has merit, since it still is unlikely that actual participant levels will ever get to 1,800. And in my mind, that would justify an adjustment of the winter launch allocation.
Of course that, and $0.37, will get you a cup of coffee at Greasy Johnny's Cafe.
This has been a sort of long way of saying that in every contact I've had with the Park where this came up, they considered the current launch cap to be something we as private boaters have to live with. But that still leaves some other things to advocate for, like longer trips in winter, dropping the one trip a year rule November - February, etc.
One final thought. The permit party approach (perfectly legal and likely never to be stopped) surely puts stand-alone lottery entrants at a significant disadvantage. I would venture that it also skews the real-world probability of getting a permit in ways that charts and graphs will never accurately represent.
FWIW.
Rich Phillips
I pretty much agree. But over the years, I sat in a lot of meetings with Park representatives back when I was on the GCPBA Board. The first and foremost perspective they have is launches, not so much user-days. They emphasize that the CRMP is a launch-based system, and that the CRMP is pretty much a closed document (aside from minor adjustments they make through what they call "adaptive management"). To the Park, lapsed ideal user-day totals are not as critical as trying to approach 100% use of all launches.
So in that context, the "let's try to get to 1,800 participants each year in the winter" argument we would make isn't as weighty. Yes, it's important to folks like us to optimize access. But in the CRMP launch context, the Park already is getting 95+% of all the scheduled launches out, and objectively that's not bad. It seems less important to them that the user-days are not similarly optimized.
As to pizzas, take that pizza and cut it in half and put each half at a separate table that requires separate linen goods, wait staff, bussing, etc. (Yeah, I know that's sort of feeble, but it's the best I can do.) In this case, the Park might argue that if you have two 8-person groups each competing for firewood, that's twice the environmental impact of one 16-person group. It's also twice the load on the beaches, since the campsite use would be doubled. This all gets evaluated in the general category, "the winter is a time when the Canyon can get a little rest."
It's not the total allowed winter launches that is immutable, it's the total number for the entire year -- 504, IIRC. They consider that number (embodied in the CRMP) just about untouchable. So absent a new CRMP, the only way they could see to add launches in the winter is to chop them in some other season.
Now I don't see it quite that way. I would argue that (notwithstanding the fact it's a launch based system) the winter component of the 504 launches was developed from some user-day use projection in the vicinity of 16 persons per trip times some arbitrary trip length. Since we now know that actual use is far less, my view is that your idea has merit, since it still is unlikely that actual participant levels will ever get to 1,800. And in my mind, that would justify an adjustment of the winter launch allocation.
Of course that, and $0.37, will get you a cup of coffee at Greasy Johnny's Cafe.
This has been a sort of long way of saying that in every contact I've had with the Park where this came up, they considered the current launch cap to be something we as private boaters have to live with. But that still leaves some other things to advocate for, like longer trips in winter, dropping the one trip a year rule November - February, etc.
One final thought. The permit party approach (perfectly legal and likely never to be stopped) surely puts stand-alone lottery entrants at a significant disadvantage. I would venture that it also skews the real-world probability of getting a permit in ways that charts and graphs will never accurately represent.
FWIW.
Rich Phillips
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