digits.gg is an online car and motorbike number plate (registration plate) valuation service in Guernsey. it also provides historical information about number plate prices.
At the moment, digits is assessing Guernsey car number plates only. in the future motorbikes and Jersey / Alderney plates will be included.
a bunch of 'rules' have been defined that describe all the aspects of a numeric number plate that make it interesting. all the common things are covered... length, doubles, triples, sequences etc. and a lot of uncommon things. there are currently around 30 rules, with more being added. these rules are used to derive a 'score' for a number plate, which then in conjunction with historic prices (e.g., from auctions) it is used to derive valuations for all number plates.
it's some pretty complex maths/algorithm/skynet stuff going on but hopefully it's pretty close.
the site uses the scores derived from the rules in conjunction with known sale prices. the problem with this is that sale prices are tremendously variable and will rarely adhere to the rules. someone might just love a number and be prepared to pay a premium for it. this is human nature but in statistics is a nightmare - ultimately prices can get skewed (up and down) but also result in a curious position whereby a higher rated plate is valued at less than a lower one!
to counter this, the site use, in simplest terms, a smoothing algorithm, that ultimately tries to see off the highs and lows of real data to paint a better picture of the world - that is that there's a positive correlation between the rating and the value. i don't like throwing away any data... but in some cases you have to. For that reason 007's sale price is excluded from the valuations!
this is a hobby project, run for a bit of a fun. we'd love to know what you think of it and any thoughts or ideas on how to improve it. if there are any bugs or other issues, please let us know so they can be fixed.