For most light construction, rules of thumb are good enough Secrets of Structural Engineering JLC - APRIL 1989 I like to think I am a mature adult and that criticism just washes off, but I thought for months about a letter published last summer in The Journal (see: "Too Many Specialists" 6/88, p. 5). In it, a reader suggested that since everyone with a decent education can handle algebra, a few formulas might be more useful than the rules of thumb I presented for designing cantilever decks. I apologize for oversimplifying; here is my confession. How We Calculate We structural engineers don't really know quite what we are doing. We try to make buildings safe and sound, but we have