Marking Errors

In a recent post, I mentioned the need to deal better with errors and statistical analysis amongst theoreticians and modellers in nuclear physics than we habitually do at present.  Apart from the fact that I'm co-oraganising a workshop on the topic, my post was spurred by a conversation I had at a workshop in Poland.  One of the comments in the recent post, about assumptions in methodology, made me think of something that I usually think about at this time of year, namely: How accurately can we measure student achievement?

We (and I mean teachers and academics in general, rather than my department at my University) set a lot of different kind of assignments for students and generally give them a numerical score for each assignment.  To make the case simple to discuss, let's restrict it to my field of Physics, where most assignments have pre-determined mark schemes, that can be very detailed and prescriptive, written at the time of setting the assignment.  I have little doubt that we can mark (quite) faithfully according to the mark scheme, and therefore give a "precise" mark (in the usual language distinguishing precision from accuracy).  On the other hand, I'm not so sure that marks are so accurate.

For example, let's say one student takes one final year module, examined by me, and another takes a different optional module examined by my fictional colleague Dr Cruel.  We have both followed the guidelines to the best of our ability in terms of matching up our assessment to learning outcomes and level descriptors, and all the other sorts of things that the educationalists have made us think about, yet the mark a student gets in my course is much higher than in Dr Cruel's course.  The student put in the same amount of work in both courses.  Is it just that they revised the wrong thing in my course?  That they found the material differently difficult?  That I am a kinder marker?  

There are probably many reasons, and to some extent, they are all just part of the system, and students (and everyone else) must accept this.  And accept that there are factors like the luck of the style of the 2013 exam being one that a certain student was hoping for and another not, or vice versa.  Still, I certainly find it hard to argue that a student having a mark of 59.2% means that a lower second degree is absolutely the obvious outcome, whereas one with 60.1% absolutely has an upper second.  Actually - I guess I don't find that hard - they are rules which are set down, but I get really frustrated by people who are adamant that we mark to an accuracy of anything below a few percent.

The Unstable Nucleus

A new nuclear physics blog has hit the streets:  Ex-Surrey (and Cardiff) student and now York post-doc Dr Gemma Wilson's The Unstable Nucleus is live and definitely worth a read.  She has already beaten me by choosing a much less unwieldy name than "blog of the isotopes" with which I have encumbered myself.  I have added Gemma's blog to my reading list, and I heartily recommend it to others!

Also, while I'm at it, if you're not reading Miss Atomic Bomb, then you are missing the other great academic nuclear physics blog that's out there, and while I'm at it, I shall put in a word for Nuclear Secrecy which is a good read, more on the history and sociology of the nuclear age.

Information and Statistics in Nuclear Theory

This post is partly an advert for a workshop I'm co-organising in Glasgow on 19-20 August.  It's called "ISNET: Information and Statistics in Nuclear Experiment and Theory".  It's all about the linked processes in (nuclear) physics of performing experiments to measure some property of a system, and developing theoretical models of the same system, and in particular how to properly quantify things like the errors and uncertainties associated with the models.  These uncertainties have not always been treated with the same rigour in theoretical work as they are in experimental, but that is increasingly changing.  If you're a nuclear physicist and fancy coming along, please visit the workshop website and register.  There is no fee for the workshop, but also no support, so your institution will need to cover local expenses.

The other part of the post is to report on some broader issues related to the workshop.  I'm in Cracow, in Poland, at another workshop (this one on things we can do if a new nuclear research facility is built).  At the end of my talk, I advertised our workshop in Glasgow, and had a very interesting conversation with Thomas Duguet from Saclay afterwards.  Amongst many other interesting things, we discussed the problem of publications only giving the story of successful investigations.  Often (or perhaps always), both in experiment and theory, the process of arriving at the point at which you have some positive result to report, has involved a lot of getting things wrong, dead ends, trying fruitless methods, before finally getting a result.  Sometimes the result is only negative, in that only the absence of a hoped-for result is "discovered".  It is certainly not the case that these things never make it into print - there are plenty of results setting bounds on the existence of physical states through experiments that have been performed and not seen anything, but there is surely a lot of work out there that is never reported.  

There are all sorts of potential effects of this.  What will a historian of science conclude when they plumb the literature many years from now?  These parts of the scientific process will be hidden.  What happens to the career of a young scientist who does sterling work that only leads to ruling out the existence of something.  How will they be compared on the job market to someone who discovers something?  Then there is the waste of repeated labour - trying to do something that someone else has already explored exhaustively, but not reported that it didn't work.  Partly because of these issues, Thomas has been discussing with journal editors about starting a new series of articles which document the process of doing science, pitfalls and all.  

Sofia to Krakow

I feel rather tired.  Yesterday I was in Sofia and today I am in Krakow.  I spent the morning yesterday working in my hotel room until it was time to check out around 11.  Then my friend and colleague, Nikolay, picked me up to go to the Bulgarian National Museum.  His family came too, and we had a nice time eating together before going to the museum.  They were really friendly and the children were keen to speak English with me, which was nice.  I say children - one is about to go to university and the other not far behind, so "children" is perhaps not the right word.  Well, obviously, they are the children of my friend but ... well.  The museum was in a pretty grand building built by the communist authorities to impress visitors.  Lots of marble and grand rooms with ornate ceilings.  

The contents of the museum are all Bulgarian-related, starting from the earliest signs of human habitation in the form of stone tools and burial mounds (In the English translations, they used the word "tell" which I didn't recognise in that context, but is plausibly correct according to the Chambers Dictionary app on my phone).  Then there were artefacts from Thracian times through Roman, Byzantine, Old Bulgarian, Ottoman, and Bulgarian, stopping at the end of the second world war, just before the communist days.  I think the most impressive things were the Thracian gold items know as the Panagyurishte Treasure.  The fineness of the craft beat most things that came later in the museum.  The picture on the wikipedia page does not do them credit.  I'm afraid I didn't take a picture, though I can't claim that my phone would have done a better job than the wikipedia article photographer.

After the museum, I was dropped off at Sofia Airport.  I had to hang around for a while before Air Berlin were ready to check anyone in, but it all worked out okay, and I flew with them via Berlin Tegel to Krakow.  I arrived at around 11pm, made it to the hotel and fell asleep, only to wake up quite early as I was fretting (unnecessarily) about being fully prepared to talk at the conference here.  I finished tinkering with my talk, and headed to the planned excursion to the museum of the University.  It's an old university, with much history to celebrate, and their museum is pretty cool.  It's in a building of the university which is still sometimes used for formal events, and there are lots of artefacts, from things used to teach astronomy at the time Copernicus was there, through to donated items from famous Krakow residents, like Oscar and Nobel Prize medals.  We waited in the cloister for the famous clock to ring the hour, which then started a slightly silly mechanical display of characters moving around it.

Then to the conference.  It was pretty gruelling, in that it started after lunch, with two session of three hours each, with a coffee break in the middle.  Three hours per session is quite a lot to deal with, and what with being a bit tired from travelling I really struggled to fight the seminarcolepsy for the first hour or so before perking up.  I gave my talk in the second half.  It was okay - perhaps not as well-prepared as my talk in Bulgaria, but fine.  Really, I can't complain about my delivery, but I'd rather have done more calculations that I hadn't already talked about elsewhere.  Oh well.  I finished the evening by finding a nice vegetarian restaurant close to my hotel and coming back to listen to the Archers omnibus from yesterday and to write this.  

Since it's nice to include a picture in these posts, I include a picture of people taking a picture of the famous clock.

O Rila?

View from conference room

Around this time last year, I blogged about my attendance at a workshop in the Rila Mountains in Bulgaria.  I came back again this year.  The view from the conference room window has not changed a lot, as can be seen in the photograph compared to the one from last year.

Probably for the first time ever at a conference I was the first speaker.  My status has reached such a lofty status (and the original first speaker cancelled).  I think my talk went pretty well.  With more preparation time, I  might have generated more movies, which always look nice, and are quite possible since my talk was on a time-dependent method of calculations, but I'd prepared well enough to talk competently and hopefully give a coherent account of the problem, and the solution.  I aim to write a separate post about the work some day.

Coming to theory workshops in Eastern Europe leaves one prey to talks assuming a level of mathematics incommensurate with my own personal reality, though I tried to fit in, mentioning a large number of so-called special functions.  It turned out I was not the only one to mention Whittaker functions, though I think only I said the name "Hankel" and pretty sure only I mentioned the Fadeeva function.  

The rest of the talks were generally pretty interesting, and came in a number of styles.  These days, with overhead projectors no longer provided at conferences, the possibility to give a talk with crowded hand-drawn acetates full of complicated equations is more limited than it used to be.  Fortunately, an enterprising Bulgarian managed to produce a series of "slides" in the form of photographs of dense hand-written notes.  I think the audience was generally quite amused with this.  I did have difficulty with some of the more abstract talks, and I could swear that one of the speakers said "to make it more difficult to understand, we can introduce the intrinsic group".  Probably I mis-heard, but it was already difficult enough for me.

Still, I have come away with a list of things to do, inspired by the talks.  In particular, AK Jain of Roorkee presented a remarkable description of isospin distribution in fission fragments.  It is remarkable because of its simplicity, the apparent agreement with experiment and that no-one had thought of it before.  I look forward to seeing the work published, and have plans to make some complementary calculations.

On the first day of the conference, I had one delegate ask to have her picture taken with me, because of the usual reason.  They should have got me to play Mycroft in the BBC Sherlock Holmes adaptation, really.

Early one morning in the Rila Mountains

Normally, as I prepare to go to a conference,  I get a talk ready, and maybe prepare an article for the conference proceedings.  Or at least, I think about preparing those two things and make sure I know that I have the means to actually write the talk on the journey there.

Next week I'll be at the Rila Mountain workshop, in Bulgaria.  It's a long-standing annual meeting organised by the theoretical nuclear physics group in Sofia, and takes place in a somewhat isolated spot in the Rila mountains of Bulgaria.  I went last year for the first time, and discovered that as well as the scientific preparation, I was obligated to provide some kind of entertainment, as the sole British representative at the meeting.  The idea is that at the conference dinner, one person from each country represented must do something, such as recite a poem, or sing a song - or even tell a joke - that is somehow related to the place they are from.  I was caught a bit unawares by this last time.  I found out either on the day of the dinner, or the evening before.  Still, it was enough time to pick out a poem by Robert Burns, though not my favourite one, which had the benefit that I would be reading something incomprehensible to the non-native speakers of Scots, just like they would be with their poems and songs.  It seemed to go down okay.

This year, I am better prepared.  In a homage to Radio 4's defunct UK theme, I have learnt to play Early One Morning on the ukulele, and will attempt to sing along to my playing.  With luck, no-one will take a movie of it and post it online.

Interview with me

A few weeks ago, I conducted an online interview about science communication.  It's online now, and reading it back doesn't make me cringe, so if you fancy reading it, take a look here.

The picture they used (because I sent it to the interviewer), on the other hand, does make me cringe a bit.  It's my official university publicity shot.  It's an okay picture, but the more I see it, the more I think it makes me look as though I am straining slightly, or can smell something bad.