[Taxacom] Google Trends

[Mike Dallwitz]

Jim Croft wrote:

> The problem with these trend graphs is that it is very likely that they 
> have been 'normalized' in some way, but just how is totally opaque.

 From http://www.google.com/intl/en/trends/about.html:

"Essentially, all results from Google Trends are normalized. This means 
we've divided the sets of data by a common variable to cancel out the 
variable's effect on the data and allow the underlying characteristics of 
the data sets to be compared."

"[The Search Volume shows] how many searches have been done for the terms 
you enter, relative to the total number of searches done on Google over time."

> I figured Yule stuff was responsible for the sharp December/January dips, 
> and had guessed at the summer holiday depression while people were outside 
> doing real things.
> 
> [Do the trends provide evidence of] deliberate policy antagonistic to 
> biodiversity?

In general, you can't draw conclusions about attitudes or behaviour from 
Google Trends, because (1) only _searches_ (and news articles) are analysed, 
and (2) the sample presumably has biases which change in the short and long 
terms.

For example, some 'frivolous' queries (e.g. 'movies') have sharp peaks at 
Christmas, and broad peaks during the northern summer - the opposite to 
'serious' queries (e.g. 'biodiversity'). This tells us nothing about whether 
"people were outside doing real things". Perhaps people made twice as many 
queries about 'biodiversity' during these periods, but four times as many 
about 'movies'.

Long-term trends may be influenced by demographic trends in Web use. Perhaps 
policy makers are making _more_ queries about 'biodiversity', but this is 
being swamped by queries about 'movies' by increasing numbers of children 
who are using the Web.

Or perhaps there is an increase in interest in biodiversity, but people are 
now so involved with it that they make more queries on particular 
biodiversity topics, rather than queries on the word itself.

 From http://www.google.com/intl/en/trends/about.html:

"Keep in mind that instead of measuring overall interest in a topic, Google 
Trends shows users' propensity to search for that topic on Google on a 
relative basis. For example, just because a particular region isn't on the 
Top Regions list for the term "haircut" doesn't necessarily mean that people 
there have decided to stage a mass rebellion against society's conventions. 
It could be that people in that region might not use Google to find a 
barber, use a different term when doing their searches, or simply search for 
so many other topics unrelated to haircuts that searches for "haircut" make 
up a very small portion of the search volume from that region when compared 
to other regions."

-- 
Mike Dallwitz
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