There are problems with pet microchips despite the fact that they are promoted quite heavily by vets and animal advocates. Also local authorities discuss whether they should be obligatory. It is worth noting, initially, that in the USA, quite a small percentage of cats are microchipped. I don’t have an exact figure but one reference book (page 72, The Welfare of Cats) states that 0.3 percent of cats are provided with microchips or tattoos for identification.
A recent story about rescuing cats and dogs from Hurricane Harvey provides us with an indication of the percentage of companion animals who are microchipped. An animal activist, Jason Cooke, was involved in rescuing cats and dogs and he said:
“The saddest thing out of all of this is that out of all those animals that came in, maybe five percent were microchipped.” – Vindy.com
Let’s just agree that the percentage of microchipped cats and dogs is low in America.
The big problem is that even when cats or dogs are microchipped the data contained in them is often out of date. I don’t have statistics from America but I do have them from Australia and the UK (source: a study).
In Australia, a study of June 2015, found that only 28% of dogs and 9% of cats were microchipped and importantly a substantial proportion, namely 37%, had problems with stored data.
In 47% of cases, the microchip data indicated that the animal was registered to a previous owner or organisation. The phone number was incorrect or disconnected in 29% of cases. The microchip was not registered in 14% of cases. Clearly when the microchip was inaccurate it was harder to contact the owner.
The proportion of animals reclaimed fell off significantly when the microchip had data problems. For dogs, when the microchip was accurate 87% of animals were reclaimed (i.e. reunited with their owner), while when the data was inaccurate, 69% of animals were reunited with their owner. Non-microchips animals were reunited 37% of the time.
For cats, accurate microchips resulted in a reunification rate of 61%. When the data was inaccurate cats were reunited with their owners 33% of the time and only 5% when there was no microchip.
With respect to dogs in the UK, 45% of stray dogs, in a survey, were microchipped. But the owners’ information stored on the microchip was out of date in half of the microchips. In 30% of cases the microchip stored an old phone number. As for old addresses, this occurred 31% of the time. And registration was to the wrong owner 25% of the time. I don’t have figures for cats but you can imagine that they will be similar (source: Battersea Dogs and Cats Home).
Clearly, far too many dog and cat owners are not ensuring that their pet’s microchip is up-to-date. This makes them far less effective.
In answer to the question in the title, it must be that micro-chipping is effective but the effectiveness is substantially undermined by a failure to update data.