BKR Blog

Presentations in conferences are typically classified into oral or poster presentations. Obviously, oral presentations are reserved for those topics which are considered “hot” and of higher appeal to the intended audience. If you want to increase your signal-to-noise ratio (here, signal pertains your scientific work, in contrast to noise, which is what everyone else is talking about), oral presentation is the way to go. This is the best way to get maximum exposure or visibility to other researchers. Indeed, this can be conveniently thought of as “parallel visibility.”

Posters, on the other hand, allows you to discuss your work to one person at a time. In contrast to oral presentations, this only allows “series visibility” of your work (and thus, lower signal-to-noise ratio). Nevertheless, this allows more in-depth discussion of your results, and even offers the possibility of networking with other people interested in your work. Some valuable ideas could come up as a result of these in-depth discussions - something that doesn’t usually come by way of an oral presentation, which is of course constrained due to time limitations.

In the biannual meetings of the Japan Society of Applied Physics (Nihon Oyobutsuri Gakkai), there are even sessions where both poster and oral presentations are combined. These are called short oral presentations with poster. Oral presentations are given for 5 minutes (usually in the morning), followed up by a 2-hour poster session (usually in the afternoon). Oral presentations usually just give a highlight of the main results, which allows the audience to choose which more interesting results to go to during the poster session.

If I were to choose, however, I would prefer an oral presentation. I find poster presentations particularly tiring, especially because most poster sessions I attend are usually two hours long. If there are is a considerable number of people who are interested in my work, that usually means that I have to stand and talk for the entire two-hour duration! Also, most of the interesting results related to my work tend to be presented in the same session, so this also means that I miss out on discussing those results with the concerned poster presentors because I have to attend to my own poster. Of course, this can also be conveniently circumvented by sneaking out of one’s poster presentation and doing the rounds of other posters. For a two-hour poster session, I think the best compromise would be to stay at one’s poster for about 1 hour, then use the remaining hour to check out other people’s posters.

What about you, what is your preference? Oral or poster?

The Hirsch number (otherwise known as the h-index) tries to quantify the (scientific) productivity of a scientist. The Hirsch number was first described by the physicist J.E. Hirsch in a 2005 PNAS paper: An index to quantify an individual?s scientific research output. Hirsch says:

I propose the index h, defined as the number of papers with citation number  h, as a useful index to characterize the scientific output of a researcher.The publication record of an individual and the citation record clearly are data that contain useful information. That information includes the number (N_p) of papers published over n years, the number of citations (N^j_c) for each paper (j), the journals where the papers were published, their impact parameter, etc. This large amount of information will be evaluated with different criteria by different people. Here, I would like to propose a single number, the “h index,” as a particularly simple and useful way to characterize the scientific output of a researcher.A scientist has index h if h of his or her N_p papers have at least h citations each and the other (N_p ? h) papers have  h citations each.

Histogram giving number of Nobel-prize recipients in Physics in the last 20 years versus their h-index. The peak is at h-index between 35 and 39 (image and text: http://physicsworld.com/cws/article/news/22890/1/050809.)

For example, if I have a Hirsch number of 10, that simply means that I have written 10 papers with at least 10 citations each.

Most of us are familiar with the impact factor, which is the commonly accepted method for measuring the scientific “weight” of a paper. The impact factor for a journal is “calculated based on a three-year period, and can be considered to be the average number of times published papers are cited up to two calendar years after publication (including the calendar year in which it was published)” (Source: Wikipedia). Currently the top scientific journal with the highest impact factor is Science (30.028) followed closely by Nature (26.681).

J.E. Hirsch further argues in a recent paper that the h-index appears to be a good predictor of one’s scientific productivity in the future.

For those of us who hate quantifying our work, and having ourselves “measured” in terms of simple numbers, it may very well be that the h-index is just another mathematical exercise that we can do without. The thought of having our CVs - our life’s work - reduced to a single number could be unnerving especially to those who are only about to embark on their scientific careers. On the other hand, knowing in advance that such a parameter exists - which could very well be the basis for evaluation in future employment applications - may also help one in mapping out the best strategies for scientific productivity and career advancement.