---
title: "My first blog post was a guest post"
layout: default
category: Etc
tags: [PVA, publications, Hungary]
published: true
disqus: petersolymos
promote: false
---

The title says it all. I wrote [this](http://okologiablog.hu/node/219) piece about
*Publication Viability Analysis* pondering about a pattern that I
observed while looking at Hungarian ecologists publication output
through time using the [Web of Science](https://webofknowledge.com/) database
(the original post is in Hungarian).

I fit Ricker growth model to observed publication numbers and a non-stationary 2-phase
model was the best fit. An intrinsic growth rate of 0.39 with
carrying capacity *K* = 14 publications per year was characteristic to
the pre-democracy (Soviet occupation era) phase (1978--1997).
The democratic era (1998--2012) showed growth rate of 0.21 with a much higher
*K* = 100 (variance went from 0.44 to 0.03).

The motivation for the analysis and post was that the number of publications
has been persistently around *K* = 100 for 5 years. So I looked at the
correlation between the number of PhD students and the number of publications,
using different lag times between 0 and 10 years. The correlation
was highest for a 7-year lag. This more or less indicates a cohort of
PhD students (myself included) who started PhD around 2000.

This cohort represents the grandchildren of the post-WWII boom,
births have declined after this cohort -- therefore less PhD students
to produce papers.
If this is true, it also means that it takes considerable time for PhD students
to reach peak publication productivity. So I proposed to shorten the lag to 3--5 years
to boost publication numbers. Win for the students and win for Hungary.

Why am I bringing this old post up 3 years later? Because I wanted to
see how well my estimates have held up from a short-term forecasting
standpoint. Well, here are the results of a recent query with identical
settings (`ADDRESS=HUNGARY; CATEGORIES=ECOLOGY`) for the years 2013--2015:

Year | Count
---- | ------
2013 | 87
2014 | 114
2015 | 108

<img src="{{ site.baseurl }}/images/2016/08/30/pva-2.png" class="img-responsive" alt="PVA">


The figure shows the two phases used in modeling (grey and gold),
and the forecast (tomato) with horizontal lines for carrying
capacity. I wish these numbers have improved, but it is what it is.
[You can't argue with science](http://comicvine.gamespot.com/images/1300-1819415).
In case you want to argue, just leave a comment!