"A/B and MVT doesn't work" on websites

A few months ago, I wrote about my experience of how modern power-tools just don't work, and how my power-drill wasn't working as well as other people said it would.  Well, today, I've just read that A/B and multivariate testing does not work on e-Commerce sites.  And I think it's true.  After all, I read it online, so it must be true.  And it matches with another recent experience I had:  it seems my car is broken.

I've had my car for a number of years - it's a very nice car and I was fortunate enough to have it from new.  It seems to drive well, but I've found that there are a number of fundamental issues with it.

Image credit

The speedometer doesn't work.  The speed readout (both digital and analogue) agree with each other to about 1%, but the maximum speed on the speedo is 150 mph, and I've never managed to achieve those speeds. I took it for a drive recently, and even though my maximum speed was 60 mph, which I achieved for a short while, it still took me 30 mins to travel 20 miles.  No - the speedometer is just plain useless.

The miles per gallon calculation on the dashboard display is inaccurate, and certainly doesn't match the driver's guide (yes, I read the driver's guide).  It keeps changing all the time - what's that all about?  Even the 'average' fuel efficiency figure changes.  Seriously?  Another important part of my car is not working properly.  The dealer says that the figures are based on "average use" (whatever that is), and over a long period of time it will average out, but I'm not prepared to wait that long.  I want to see my driving data match the actual data all the time.

Image credit

The rear-view- and wing-mirrors only show me where I've just been, and - worse still - the image is reversed (transposed left to right, horizontally).  Honestly, just how am I supposed to make sense of the image - or see where I'm going - by looking in them?

I have my own satnav - it's a mid-range TomTom model, so it's good and reliable - but when I use it in my car, the satnav predicted arrival time is wrong.  Worse still, the satnav (which has full maps of Europe) won't integrate with the car's engine and drive it for me, so I am stuck with still having to actually drive the car myself.  And did I mention that the speed readout on the satnav doesn't match the car's speedometer?

Image credit

I have driven the car in heavy traffic and along long stretches of motorways; it's covered country lanes and suburban housing estates - but it's only occasionally performed as well as it's supposed to in the manual, and it only rarely displays MPG figures that match my own forecasts and predictions.

To be honest, the only things that really work as I expect them to are the odometer (mileometer) and the clock.

I've tried monitoring engine temperature (the engine is cold when it starts in winter and is generally warmer in summer); oil pressure (unaffected); brake pad usage (it goes up when I travel through busier streets) and so on, but none of these metrics have been particularly useful at helping me drive better, faster or further.

I've attempted to forecast my future mileage, fuel efficiency and average speed based on the distances I covered yesterday, last week and last month.  It's almost impossible - it seems that it varies day by day.  Having said that, we went on a family holiday round North Wales last August, and I know we're not going this year, so I can expect a decrease in my average mileage for this year.  And my fuel efficiency will be lower because I won't be driving as many of the long, steady dual-carriageway runs that I did last year.  But these are just estimates really, based only on actual events that happened last year but won't happen this year.

My car is on a three-year lease, and the lease expires next summer.  I will probably swap it for a different car, but I'd like to know how that car's fuel efficiency and speed performance will compare with my current one.  Not just what the rear view mirrors look like, or the maximum speed on the speedometer, or even what the driver's manual says. 

Perhaps I should continue to drive as I usually do for the next 6-12 months, and ask someone to drive around, following me, in my potential purchase.  Then, next summer, maybe we can compare their actual performances and choose between keeping my car or swapping it?  Who knows?

I've used car performance as an analogy to online testing before:
How long to run an A/B test for? (2013)
Who holds the steering wheel? (2011)