I've got lots of work in advanced statistics (Quality Engineering), and am happy to chime in.
What you're suggesting is a fun way to really get people's heads in a tizzy. Basically, these types of "formulas' attempt to take quantitative data and provide a probability of occurrence. This issue you're going to find is in a few points:
1) Unless you can guarantee the data is accurate, you can't properly predict outcomes. For example, how will you determine if something has been "detected?" and to what extent with what equipment, and what coverage?
2) Variation in underlying statistical probabilities. Basically, variation in #s around things like "location activeness" doesn't account for things like seasonality, activities which cause specific losses (like removal of gloves, or application of sunscreen/lotions for rings). Attempting to apply a single number or categories of numbers only increases the variation in the data (decreasing the probability of accuracy)
3) How will you determine probabilities? With a large enough sample population over a long enough time, you'll eventually get a nice Gaussian distribution (normal bell curve) for drops. This is how insurance companies can create actuary tables over population distributions... What you're talking about though is a single isolated point in what is very likely a SHORT time frame. The result is a drastic decrease in predictability, as the possibility of a normal chance occurrence is anywhere within 3 standard deviations of the mean average. (Speaking in lay terms, you can't predict a short term event probability in a very small sample size with any degree of accuracy. You might get lucky, but that's it.) This is why attempting to create a simple formula based on 10 people (or even 1000 people) won't work. You might pull it off (if you had the data) for 10,000, but even then drops don't equal finds!
Just the three above points make it darn near impossible to create a prediction rule with any degree of accuracy. The only thing you're going to get is the information you already know. Things like
- "lots of people in an area in a short amount of time increases the probability of drops."
- "A few people continually visiting in an area over a long amount of time increases the probability of drops."
- "Detectorists in an area reduce the amount of drops available"
- "Demographics (wealth, displays of wealth) of an area increase/decrease the likelihood of valuable drops"
- "Previously unsearched areas increase the likelihood of finds."
All of these things can only be qualified, rather than quantified (not enough long term data collected). As a result, if you were to put all of this together, you'll likely end up with the same list of places that are already qualified, namely:
Parks, beaches, schoolyards, tot-lots and whatnot are great locations.
Parking lot strips, sidewalk strips, skilifts, etc... are all also higher probability locations. Is it a guarantee? nope.
Even a field that gets used as a fair for a short period is likely to have drops... but not guaranteed. Drops are great... how much of it gets picked BACK up is beyond me. Those are the numbers that we can't get! Being able to determine when someone loses something and doesn't look for it, is really tough!
In the end, you can put together a quantitative formula, but it will be no more or less accurate than other qualitative evaluations, simply because the data isn't that accurate.
AND... there's the basic "eyeball" of a situation. I find 2 to 3 times the volume of what my buddies do when we go detecting, because I've learned to simply ask "where would people lose stuff?" A small hill there, a light post here, an open field where lots of things get thrown around... Those target areas become the mines... but I've only found HALF of my best finds searching expected locations. the other half typically comes because I'm walking in the middle of nowhere, and swinging the coil and BEEP! I get a strong signal. There's no reason that gold ring should be THERE... but it is. Go figure.
Basically, it comes down to the fact that your inputs aren't going to be any more accurate than simple comparisons would already give you (you already know a beach populated by sun-bathers is more likely to have jewelry drops than a beach that's filled with fishermen, do you need a number?)
Better, Better yet, and Even Better than that... Qualitative analysis works, but it's the weird crap like "I found the sapphire ring in my front yard, it's worth $15K, and I live in a neighborhood that makes $50K a year"that doesn't make any sense. I always chuckle when I read someone's post that says "eventually if you dig enough pop-tops you will find a gold ring." Uh... nope. That's just statistically not true. Does your probability increase? YES... is it a guarantee? NO.
Just ask me... I've found four gold rings, and probably have dug no more than 500 bottle tops. Why can I get so lucky? Because I'm swinging the coil in an area that someone dropped something. That's simply chance working both ways (that someone dropped something, and I happened to swing my coil over it). By the time I'd found my third gold ring, my son had swung about a half of the hours I had, and he was actually on EVERY hunt, just hunting in an area that was also "looking good" but didn't have a gold ring in it. Poor kid. Just unlucky!
Probability is not a guarantee..> Correlation is not causation, and being lucky is better than being good, sometimes!
Skippy
