To measure the height of a child as he or she grows, the engineer will make sure it is accurate. That is his job.

This may involve some whining from the child and a few smart comments from his wife, but to get a measure in which one can be confident takes a little work. This means don’t rely on those doctor office contraptions. I have never trusted them. The nurse has the kid stand up on them, may tell them to stand up straight, may not, and then flops this metal arm on their head that may or may not be horizontal. Engineers do not appreciate flippant approaches to measurement.

The way to do this correctly is to get a straightedge that is also a level, the kind with the bubble in the glass cylinder. Have the kid stand straight as they can against a wall and place the level on their head, making sure it is, well, level. But how straight the kid stands and where the level hits on their uneven heads, along with possibly a few other variables, will not assure this to be an accurate measurement. So, here is the key. Take the measurement numerous times. I will not tell you how many, but it is more than two. Have the kid step away from the wall, then back against it, and place the level on his or her head and make a mark – and do this many, many times. You will then see that the field of measurement, particularly when a variable like a child is involved, is not an exact science. But at least with a number of measurements, you will see that their may be a few outliers, but many of the marks will be bunched together very closely and the average of those can be taken as the best measurement of the child’s height.

By the eighth time or so, the child may complain about stepping away and standing up again. Remind them that is only done once a year, or if you really like tracking height progression, once every month, and also remind them of the confidence he or she can have in “knowing” how tall you are (in English and metric units), rather than a sloppy, “Yeah, I’m about 4 feet 8 inches that friends who rely on that doctor office measurement can only say.

I think I’ve proved my point here.