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Things I have Learned About Trackables--Drop Intervals

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My previous posts compared consecutive one-year trackable data sets followed for the index year and the following two calendar years. I used this approach to determine if there were discernable differences in survivorship from changes made over the years in either trackable assembly, changing the mission statement, or selectively releasing trackables. It has been made clear that there is little this trackable owner can do to increase longevity beyond using durable materials. The fate of trackables is wholly in the hands their finders.


This post, and at least two others to follow, draw from a data set consisting of all my 1,710 trackables released in the five calendar years 2010 through 2014. Their activity was monitored for the next five calendar years, ending 31 Dec 2019. Thus, the youngest trackables would be at least five years old, and the oldest could be near ten, assuming survival.


I maintain separate spreadsheets for each series of trackables I have released…poker chips, art, patches, beads, etc. For this project, I pooled all the first-five-year trackables into a single spreadsheet, a portion of which is shown in the figure below.


The release date is either when I placed the trackable in a cache or when I handed if off to another cacher…it is when the trackable is released to its fate.  The release date is not the same as the activation date, which can occur days or even months earlier.  The red column displays the dates subsequent Drops occurred.  The E columns are the Elapsed days from the previous drop.  The C columns are the Cumulative days from the release date.


All of the values in the columns will be summarized in later reports, but this post is focused on the E columns, where we can begin to address questions about trackable movement.  First, I must provide some context. 


The survivorship curve for this 5-10 year data set is shown below.  The point to be made is that despite starting with a substantial sample size of 1,710 trackables, only about a quarter of the potential intervals were available to contribute to the data in the table that follows. All the space above the blue columns represents missing trackables, whereas the area defined by the blue columns represents only those trackables that provided information. Thus, every outcome from the data must be prefaced with the words “Among the trackables that survived…”


The number of intervals contributed by Individual trackables equals the number of drops and ranged from one to 67 among the trackables, with an average was around 12 drops per trackable. Consulting the bottom of the small table below, we see there were 15,150 drop intervals recorded among the trackables that could be studied.  The intervals were measured in days and range from 0 (for consecutive drops occurring on the same day) to one trackable that had an interval over seven years. 


The table also show that most (66%) consecutive drops were within 2 months (60 days) of each other.  Consecutive drops averaging 60 days will yield an outstanding six drops per year, in my opinion.  However, I will show in a later post that only a few bugs in Europe have actually maintained that pace.


Approximately 31 percent of the intervals fell within the range of two to 12 months, which, combined with the 60-day percentage, shows that 96 percent of the intervals are at less than 365 days (1 year). 


I will note in passing that a suspicious number of the trackables whose last intervals were above two years were never active again.  This suggests that no small number of cachers use phantom drops to remove lost or stolen trackables from their inventories. Therefore, these data go on to suggest that, while not quite probability, if a bug is inactive for more than a year, there is only small chance to continue traveling.


Once again, these data are derived solely from my collection of trackables.  The extent to which their activity mimics that of the collections of other cachers is unknown.  I accept there may well be differences based on regional patterns of husbandry and access to high-traffic caches, but I would bet that any other US-based collection of trackables would produce results very like these.





Edited by shellbadger
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