I've frequently been asked the question "How long should it take me to climb X"? Of course I can't give a useful answer without having a pretty good idea of the fitness and skill level of the person asking the question. Guidebooks and park hiking guides typically give very conservative, pretty slow estimates.
I had a thought about using a calibration versus the records on the fastest known times site. http://fastestknowntime.proboards.com/
As an example, say a person took 10 hours to climb or hike a given ten mile route. The FKT on that route is 6 hours. Their pace is 1 mph. The FKT pace is 1.66 mph. Their pace is then 60% that of a record. They then want to predict how long it will take them to to do a different 15 mile route where the FKT is 4 hours. The FKT pace is 3.75 mph. Multiply by 60% = 2.25 mph. 15 miles/2.25 mph = 6.7 hours. Of course the actual outcome can be heavily influenced by weather / conditions. But at least it's a means to make a reasonable quantifiable estimate. Of course if there is no record posted it isn't of much value.
This type of approach was adopted a long time ago to produce Master's Age Graded tables for competitive running. Basically scaling everything to a percent of world record pace for a given age and gender.
What do you think? Is this useful? Potential pitfalls?