annual report<\/a> (p129), 95.5% of letters are delivered on time, and 98.8% are delivered within a day of the expected time.<\/p>\nThis leaves 1.2% unaccounted for. Some of them may have been delivered later still – perhaps within the “week or two” deadline I set. Some may have been delivered to the sender. Perhap the proportion that were lost is much smaller.<\/p>\n
Furthermore, I can hope to do better than the average by taking a few simple precautions – making sure I get the destination address right, having a relatively straightforward destination address, writing clearly and ensuring there is sufficient postage.<\/p>\n
Nonetheless, I am going to assume that all 1.2% are lost for this next calculation.<\/p>\n
Similarly, I would expect that the Express Post and Registered Mail have higher<\/em> reliability figures, due to the additional scrutiny, but I have no support for that claim, so I am treating them as regular letters for this next calculation.<\/p>\nIf we successfully send the $1000 letter 98.8% of the time, and lose it entirely 1.2% of the time, we have an “expected value” (in the statistical sense) of $988. We lose $12 in value through the unreliability. (Realistic figures would be reduce<\/em> that $12.)<\/p>\nThat is a very useful figure, as it gives an upper maximum of how much we are willing to spend to further protect the asset. If we spend more than $12, we will be losing out. (That is, for every 1000 letters we send, we will have less money and assets at the end.)<\/p>\n
So, we can rule out couriers. Even if their price was a quarter of the quote that I received, and their reliability was 100%, it still wouldn’t be good value.<\/p>\n
The next question is whether a registered letter is better than a normal letter. The $100 insurance is worth $1.20 (1.2% chance of receiving $100), so the premium we are paying is $3.40 – $0.55 – $1.20 = $1.65. That requires the receiver to sign a card to receive the letter, and that card is then sent back to the sender. It provides a level of non-repudiation; the receiver can’t deny that the letter was in their control. <\/p>\n
Is that worthwhile? That depends on how frequently the recipient loses their mail and blames it on the Post Office! It also is probably of great assistance if the Post Office does lose the mail – it proves (?) that you sent it. In my case, I have decided that this is worthwhile, but not based on clear facts.<\/p>\n
Which leaves the question of insurance – each additional $100 insurance is worth, at most, $1.20 to us, but costs $1.30. Therefore, we should not accept the insurance.<\/p>\n
As always, with insurance, it is a poor bet from an expected value perspective. If this letter represents your
last<\/em> $1000, it probably has more utility to you than 1000 times the marginal utility of $1. In which case, this argument wouldn’t hold. Similarly, you might not use this argument when evaluating home insurance. It would be even more inappropriate for evaluating health insurance or public liability insurance, because your costs might be more<\/em> than your current assets.<\/div>\nIn conclusion, I haven’t proven that Australia post is more reliable than couriers, or even equally reliable. I haven’t come up with a particularly accurate estimate of the reliability of a clearly and correctly-addressed piece of registered mail. However, I have come up with an upper-bound to how much you should be willing to pay for higher reliability and for insurance.<\/p>\n
From that, I can conclude uninsured mail (perhaps registered) is a better option than insured mail or couriers that charge significantly more than Australia Post.<\/p>\n
For previous discussions about economics and Australia Post, see
Separation of Church and Postage<\/a>.\n<\/div>\n","protected":false},"excerpt":{"rendered":"Should you use Australia Post or a courier for reliable delivery of valuable documents?<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_s2mail":"","footnotes":""},"categories":[31,29,21],"tags":[],"class_list":["post-1170","post","type-post","status-publish","format-standard","hentry","category-geek","category-influencing-others","category-observation"],"_links":{"self":[{"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/posts\/1170","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/comments?post=1170"}],"version-history":[{"count":6,"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/posts\/1170\/revisions"}],"predecessor-version":[{"id":1178,"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/posts\/1170\/revisions\/1178"}],"wp:attachment":[{"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/media?parent=1170"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/categories?post=1170"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.somethinkodd.com\/oddthinking\/wp-json\/wp\/v2\/tags?post=1170"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}