Evidence everything!

Matthew Partridge explains why following the advice of your peers isn’t always best practice – especially when it comes to experimental set-up Scientists are not infallible. In Research, we always strive to follow the scientific method to resolve problems but sometime a bit of human fallacy creeps in and occasionally you find scientists doing very silly things because "that's just how it works" or "the previous student said I had to do it that way". For example; I was told a story about an Atomic Force Microscope (AFM) in a lab that was the most temperamental AFM anyone had ever used. Almost everyone that tried to use the AFM would be frustrated by terrible pictures and strange results. However, there was one old lecturer who used the AFM and every picture he took was perfect. So that person quickly became the defacto-go-to-guy for AFM photos for years because that was easier than working out why. Eventually (after some time) some smart researcher realised that it wasn't just because that lecturer was gifted but because he wore posh leather shoes which earthed him, preventing the build-up of static. What this example shows is that even in science, people are a bit prone to repeating things/methods they don't quite understand just because they think it will make the thing work better. These aren't always as clear-cut as wearing leather shoes, sometimes methods grow and evolve over time. I know an example where the manual said "insert device, remove and insert again" (don't ask, it was a strange machine) which over a period of several years was re-translated to "Oh, with that machine, you have to insert and remove six times". The evidence for the six times as opposed to once was simply that previous operators kept telling new people that it had to be inserted and removed 'at least' x times and when the next person was trained they over-compensated and made it x+1. I bring this up because that's what I've been doing this week – I've been investigating our very own lab tradition in how we run one of our lasers. Which it turns out was nothing but several operators' worth of cumulative legend. While being trained on our laser system, I was told that it had two distinct phases to its turn-on procedure. First, warm up, and then stabilisation. The warm up period, I was told, must be two hours, after that I flick a little switch and then it starts stabilisation which then takes around an hour (three hours total). This was in contrast to the instructions that were taped to the door of the lab, which said 1.5 hours for warm-up and 30mins for stabilisation (two hours total). The reason for this difference was explained as 'yeah, we used to do that but we added more time to be sure'. At this point tiny alarm bells started going off in my head, so to try and silence them I dug a little further to find that the manual for the laser (which is admittedly a little old now) said yet another set of times – 30mins for warm-up and 30mins to stabilisation (just one hour total!) The warning bells upgraded to klaxons.... or I have tinnitus. I should probably get that checked... Now, I should be clear – I'm not saying that building better protocols based on years of experience is bad, I'm merely trying to highlight that sometimes, it can end up being a cause of more problems. Increasing the warm up time has several problems for us – for a start, it may shorten the laser's life but also, it gives any experiment no matter how quick an automatic three hour setup time. Luckily for me, the stabilisation of a laser is an easy thing to check. The slowly increasing timescales were all in the name of achieving a stable power output so checking the stability was a simple matter of hooking up a power meter to the front of the laser and logging the output during these warm up phases. As you can see, the data is pretty conclusive that the laser doesn't need several hours of settling time, it's actually stable (baring a little noise) within just 10mins. It seems crazy to me now but every time the warm up and stabilisation times were reviewed before, the default response was to increase them, not to actually collect some evidence. But now that I've taken the time to check the process, we'll be going back to the original 30 minutes plus 30 minutes method, saving me (and the three other people that want to use the laser) two hours every day. Moral of the story; evidence ALL THE THINGS! Like Matthew's work? Check out his regular column here