# Introspection

I’ve been working on a lot of things of late, but none are yet in a state to show here yet. However, when talking to a colleague last week, I found it hard to explain why I do what I do: why I am so focused on metrology. But maybe I can explain it a little here (warning: rambling ahead! I have been reading books and may come over as slightly lyrical).

## Why do I think metrology matters?

It is extremely easy to fool yourself, wittingly or not. Feynman saw this, Ben Goldacre sees this, and it is painfully evident from some of the small-angle scattering work out there that it is still easy. We are built to believe.

Science provides a critical method to hinder us from fooling ourselves, but it obviously isn’t enough to stop us completely. Small-angle scattering is one field where it is immensely easy to convince yourself that you are seeing evidence for something there isn’t. There is useful information in a scattering pattern, and it is the frequency of lengths in and between contrasting features. It is not easy to get this information, and it is not easy to interpret it.

Many instrumentation suppliers will have you believe that it is a done deal, that (with their instrument), the results will come easy, be unambiguous and rock-solid. Some companies may have achieved this (I have yet to evaluate some promising offerings like Xenocs‘ and SaxsLab‘s), but I have not seen it yet. I find that if you scratch away that thin layer of veneer, the bugs come out: the lack of attention to essential uncertainties, the limited and crude data analysis methods and inadequate training required to get good data. For now, it appears that you need experts to get good results from SAXS machines (no different from the field of electron microscopy, for example).

Lastly, I think metrology matters for egoistic reasons: I am a bit of a “geek”. It is said that the essence of geek is the obsession over details, the drive to know exactly how something works. While this bears striking resemblance to mild OCD (and these days you’d probably get medicated to high heaven for showing any interest in anything out of the advertised normalcy), it is a power that can be used for good. I take pride in knowing how things work, in the ability to turn scrap into machines. Likewise, I feel a need to know how data collection and correction works, and I need to know I have done my best to present you with something worth looking at.

## How did I get here?

What started me off trying to correct scattering (during a fun company internship at Teijin Aramid) was the realisation that the scattering wavevector (I was still working in s back then) was only approximately $2 \theta/\lambda$, and that it should have been $2 \sin(\theta)/\lambda$. A minor correction for small angles, but it was fun to implement and assess its effects on the data.

Furthermore, I started in the way most people start in small-angle scattering, by linearising data and fitting linear relationships to it. I never got very far with that, the data was never really linear enoug, and the results I got were strongly dependent on the range I applied it to!

During my master’s degree project, obsession over detail was required to get the right answer (well, to not get the wrong answer would be a more correct way of putting it). Here, I got a little help from my eastern european colleague, who enjoyed pointing out all the pitfalls in computational chemistry by guiding me so I could fall into these pitfalls by myself, and pulling me out of each one.

When I started out on my Ph.D. project, again on scattering, I started getting the same ambiguity in my data as I had before. This time I had three years, though, so I decided to try and get the right data, and the correct results. I was supported in this by my Ph.D. supervisors (1, 2, 3, 4), who told me that it is important to make publications you are proud of, rather than focus on the number of publications (though I may have taken that a bit more to heart than they initially intended). About seven years have passed since the start of my Ph.D. project (and four after its end), and I’m still working on getting the data right and the results correct…

## Where are we now?

In summary, I think I can now get good data from a variety of instruments. Looking back at my publications, I can say that I am indeed proud of everything I published. However, I always worry about the small number of publications in comparison to some of my more prolific colleagues. I have been advised by a few colleagues and friends that focusing on metrology is a dead end, that I should be measuring and publishing more.

They may be right, I do find it hard to convince others that metrology matters, that getting the right results is important in this age of McDonalds publishing (fast, cheap and leaving a nasty taste in your mouth). But I like doing what I do, and for now (and the next six months), I have the freedom to research what I like. In six months I could be panhandling on the streets, but I will have had fun gettting there. And if, one day, someone sets off on the same path as I did, I hope they can use my experiences to fast-forward their own.

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