T is for TLA

What's a TLA? It is short for "three letter acronym" (and is itself a TLA, making it autological, a word possessing the property it expresses). Engineers do love a TLA, and my dictionary is consequently going to have lots of them.

I was discussing the way in which our TLAs can be shibboleths (things which tell people which group we belong to) with a colleague this week. For example, what does BOD mean to you? Basis of Design or Biochemical Oxygen Demand? If you chose the second, you have had exposure to the environmental sector. How about BAT? Your answer tells us whether you are influenced by US or EU legislation. CIP? Is it Cleaning In Place, Cold Isostatic Processing, or Constant Injection Pressure? Your choice tells us something about you, (as indeed does whether you needed me to define TLA for you)

TLAs may be even stronger indicators of which tribe of engineers we belong to (or worse yet, indicators that we aren't really engineers at all) than the terms they stand in for, due to their opacity. You might have a chance of guessing what the term a TLA abbreviates means, but the TLA itself is impenetrable jargon. Some consequently define TLA more loosely as any confusing acronym, therefore including the two, four and five letter acronyms we are only slightly less keen on. Perhaps those who coin these almost-TLAs could try harder. There are after all 17,576 potential TLAs to choose from, and each of them may be used to mean several different things, as illustrated above.

This takes me back to my original motivation in writing a dictionary - I found in researching my earlier books that our tribes use different words to mean the same things and the same words to mean different things. At least TLAs are obviously opaque, but the maximum chance of misunderstanding arises when the differences between meanings are small but significant, and especially when the terms seem like everyday language, but are not.

If there is a single quoted "operating pressure" for a reactor, is it the average or the maximum pressure? Is it the same as "working pressure"? How does it relate to the "design pressure" and the entirely unambiguous MAWP? Is it enough to quote a code or standard in order to make our meaning clear? Will this approach hold up if our understanding is tested in court?

When I have been an expert witness in cases which revolved around the meaning of words explicitly defined in explicitly referenced codes, things were not as cut and dried as you might imagine. We should make sure that the meaning of any key terms we use is understood by all involved and ideally that we have agree this explicitly somewhere in writing.

All of the terms we use to communicate with others are in essence stand-ins in for ideas in our minds. If we do not have a shared understanding of what is represented by a term, it is worse than useless. We must first understand that terms may be used by others in ways that differ from the way we use them. I find some engineers have trouble with this concept, and insist that terms have only one meaning, (that used by their tribe) and all other uses are simply wrong.

We should therefore be especially careful when we are communicating with engineers of other tribes, (or worse yet, non-engineers) unless we'd like things to get FUBAR (an example of a XTLA). Always remember that ultimately, if things go wrong, lawyers will decide what the terms we use in our professional interactions mean.