I’ve used the term Innumeracy here to describe the equivalent to numbers what illiteracy is to reading. However, I now seek a stronger word or phrase to describe the egregious claims I’ve run across. I’m leaning toward “numerical blasphemy,” but am open to suggestions.
A Money Merge Account agent sent me a link to a You Tube video titled Truth in Lending. The author wanted to illustrate the concept of “front-loaded” interest on a 30 year mortgage. I’ve never seen a post that started with that idea end in anything that made sense, this video was no different. The video itself was well done, nice animation and voice over, but the numbers soon fall apart. I’ll offer two screen shots that show this.
As this slide came up, it seemed innocent enough,unfortunately it ends incorrectly. When working with a financial calculator you need to be very specific. N is not the number of years but number of payments, in the video’s example, 360. PMT, the payment, can be positive or negative depending on the calculator. Excel looks for it to be negative, a classic TI BA-35 calculator, positive. PV is not the equity built, but the present value of the mortgage, starting at the borrowed amount, and of course, ending with a FV (future value) of zero. He then says Compute, but there are two variable missing, %i (the interest rate) as well as FV. So, while I have no idea what his intention was, he now suggest taking I (the interest rate, I suppose) and dividing by Y (years, but why?) to produce a number which is admittedly large but meaningless.
Here, you can see that he author suggests that somehow the interest rate over 15 years is over 24%. But, back to a calculator or spreadsheet, we can see that PV = $200K (original loan) i = .5% (monthly rate or 6%/12) N=360 months (30 years) FV = 0 (after 30 years it’s paid to zero. If we enter these numbers we can comput the missing variable, the payment, which is $1199.10. Then it’s simple to set N to 180 (year 15) and compute the new future value, $142,097.69, as he shows above. On the other hand, we can enter PV =$200K, i = .5%, PMT = $1199.10, N=180 and FV = $142,097.69, and ask to calculate the rate, which of course comes back as .005 or 6% per year. By the way, it’s easy to look at the interest column above and divide say, the 2021 interest into the prior year ending balance and see you get under 6%. A couple hundred video views and no one saw how silly this all was?
As far as front loading is concerned, there’s nothing diabolical in how mortgages are calculated, you owe interest on the principal outstanding at any given time. Since you owe far more in the early years, more of your payment is interest. On this example $200K mortgage, in the first month the interest is $1000, but the principal paid is only $199.10. Pay more if you wish, that’s your decision. But don’t fall for an abomination of bad math. What does this have to do with the Money Merge Account? Only that every time I see numbers abused this badly I’m reminded of my friends at UFirst and the MMA.