[MARMAM] data exploration paper

Highland Statistics Ltd. highstat at highstat.com
Wed Nov 25 08:22:19 PST 2009

Members of MARMAN involved in data analysis may be interested in the 
following paper:

A protocol for data exploration to avoid common statistical problems 
(2009). Alain F. Zuur, Elena N. Ieno  and Chris S. Elphick. Methods in 
Ecology and Evolution.

1. While teaching statistics to ecologists, the lead authors of this 
paper have noticed common statistical
problems. If a random sample of their work (including scientific papers) 
produced before doing
these courses were selected, half would probably contain violations of 
the underlying assumptions
of the statistical techniques employed.
2. Some violations have little impact on the results or ecological 
conclusions; yet others increase
type I or type II errors, potentially resulting in wrong ecological 
conclusions. Most of these violations
can be avoided by applying better data exploration. These problems are 
especially troublesome
in applied ecology, where management and policy decisions are often at 
3. Here, we provide a protocol for data exploration; discuss current 
tools to detect outliers, heterogeneity
of variance, collinearity, dependence of observations, problems with 
interactions, double
zeros in multivariate analysis, zero inflation in generalized linear 
modelling, and the correct type of
relationships between dependent and independent variables; and provide 
advice on how to address
these problems when they arise. We also address misconceptions about 
normality, and provide
advice on data transformations.
4. Data exploration avoids type I and type II errors, among other 
problems, thereby reducing the
chance of making wrong ecological conclusions and poor recommendations. 
It is therefore essential
for good quality management and policy based on statistical analyses.


Kind regards,

Alain Zuur


Dr. Alain F. Zuur
First author of:

1. Analysing Ecological Data (2007).
Zuur, AF, Ieno, EN and Smith, GM. Springer. 680 p.
URL: www.springer.com/0-387-45967-7

2. Mixed effects models and extensions in ecology with R. (2009).
Zuur, AF, Ieno, EN, Walker, N, Saveliev, AA, and Smith, GM. Springer.

3. A Beginner's Guide to R (2009).
Zuur, AF, Ieno, EN, Meesters, EHWG. Springer

Other books: http://www.highstat.com/books.htm

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