Confidence Intervals for Animal Resource Selection

Confidence Intervals for Animal Resource Selection

(Question posed and answer given on Research Gate)

What is the best method for determining the Confidence Interval of Animal Resource Selection datasets?

I am not sure what your data set looks like.
However, a very general method to get confidence intervals for any statistic of which the probability distribution is not available, is by bootstrapping.
This can be done using the freely available, high quality R statistical package.
Regards.
Herman

And on Mohammad's further question after bootstrapping using the statistical package R:

Dear Mohammad,

There is a package called boot which you have to load.

Note that using R is not straightforward, but it has excellent online documentation.

So if you are not familiar with it, you have to take some time to familiarize.

As to the boot package, as a result you get several confidence intervals.

The preferred one is BCa (bias corrected and accelerated), but it not always

converges. You have to take a look and pick another one.

The package is based on Efron and Tibshirani's book:

Introduction to the bootstrap (1993).

Furthermore, if you have SPSS available: it has provisions

for bootstrapping also nowadays.

They may be less general than provisions offered

in R which allows to program a function that calculates

the statistic you want to bootstrap.

There is also the book by myself, Don Mellenbergh and David Hand:

`Advising on research methods: A consultant's companion' (2008)

which gives a concise but clear discussion of the bootstrap.

It has also been indexed for Google Books, so that you

can consult it online. See: www.jvank.nl/ARMHome

Best,

Herman

Calculate interobserver agreement

Which one is the best way to calculate interobserver agreement related with behavioral observations?
I became a member of Research Gate (http://www.researchgate.net/home.Home.html). Below one of the questions and the answer formulated by me.

Which one is the best way to calculate interobserver agreement related with behavioral observations? (lizard stress study)
A colleague and I performed a study with lizards, where we subjected them to 4 different types of stress (cold, heat, low frequency noise and high frequency noise). We have videos of the behaviors they expressed during the experiment (flicking, head turns and so on). Now to begin the analysis of the videos, we need to make sure that our observations are more less the same, so we can exclude differences due observers bias.

We have agreed on the behaviors that we are recording and some of them are frequencies of events meanwhile others deal with duration of events. So far, we have the data of a section of our recordings that we analyzed separately and right now, we need to statistically probe that the data each one produced has no meaningful differences. Is there any statistical method you recommend?

Karen Mancera

There is a difference between assessment of association and assessment of agreement between observers.

If the variable for which you wish to calculate the agreement between observers:

a) is continuous (or ordinal with more than 5 values) things are easiest: you can use variance component analysis and calculate the interclass correlation coefficent (ICC), possibly corrected for any background factors (See: Snijder & Bosker, below). Use procedure VARCOMP in SPSS (or a similar procedure in R)

b) is dichotomous or categorical, you can use Cohen's kappa. Kappa can be calculated in SPSS using the RELIABILITY program.

c) is ordinal (with less than five values): use weighted kappas (weights concern off-diagonal distance in a observerXobserver crosstable for the item to be assessed). This can also been done in SPSS. But even if the number of options is less than 5, you can also apply variance component analysis as in a). Actually, the quadratically weighted kappa is equivalent to the ICC.

For b) and c) there is also a commercially available program called AGREE developed by Popping.

a) can also been done using multilevel analysis (cf. MLwiN), but that requires some extra skills.

All the above can be found in section 17.8 (page 453) of Adèr, Mellenbergh & Hand (2008), which also gives the appropriate references. This book is indexed for Google Books. Use the book's website to consult GB on this topic: www.jvank.nl/ARMHome

Herman Adèr

Adèr, H.j., Mellenbergh, G. J. & Hand, D. J. (2008). Advising on research methods: A consultant's companion. Huizen, The Netherlands: van Kessel.

Snijders, T.A.B. & Bosker, R. J. (1999). Multilevel analysis: An introduction to basic and advanced multilevel modeling. London: Sage.

A log book or diary to track all the steps taken for a project

A log book or diary to track all the steps taken for a project,

I became a member of Research Gate (http://www.researchgate.net/home.Home.html).
In the next posts I give some of the questions and answers formulated by me.

The first one is posted by Julia Law:

Diary of research steps as preface to writing up methodology
I would appreciate advice on methods used to write up a log book or diary to track all the steps I am taking for a few projects I am working on. I would like to develop a template to use for future projects also, so any suggestions as to what works and what doesn't would be appreciated. Thanks!

Your question is an interesting one. I have done some work on this problem.

But the way you formulate your question is a bit to general to answer in a satisfactory way. In particular, it is unclear in what field of research your projects are. Different disciplines have different methods to plan and specify research. For instance, in Medicine it is usual to formulate a protocol that is first thoroughly discussed by a local research committy before it is submitted to a medical ethical committy for assessment. There is also a diagramming method developed to specify a clinical trial (CONSORT statement), although I am doubtful about its usefulnes. However, most medical journals require such a statement for articles that describe intended research.

I have stressed the importance of properly documenting the steps taken in data analysis in our book (See Section 15.1 in Adèr, Mellenbergh and Hand, 2008). I also proposed a special diagramming method to represent methodological knowledge (See Appendix B of the same book). But in practice projects are quite varied and it is difficult to think up a general method to formally specify research procedures, let alone to develop a template that could be generally used. But maybe your own projects are quite similar and then the above may be useful.

Finally, for my own projects I always use a program called `Advanced Diary'. It is commercially available for a few dollars and makes it possibly to log each of your projects separately.

I hope this helps.

Herman Adèr

Adèr, H. J., Mellenbergh, G. J. and Hand, D. J. (2008). Advising on research methods: A consultant's companion. Johannes van Kessel: Huizen, The Netherlands.

The book has its own website: www.jvank.nl/ARMHome that links to Google Books so that you can inspect it online.