Fun With Ngrams: Grateful Dead and Jerry Garcia, 1965-1995

Here's the bigram relevant to evaluating some hypotheses I ventured in my"Garcia and Marley" post. 
Figure xxx. Google Bigram: "Grateful Dead" and "Jerry Garcia", 1965-1995


In that post, I hypothesized that "Jerry Garcia" and "Grateful Dead" would show an uptick 1986. On visual inspection the GD claim looks rightish: the 1986-1995 slope should be statistically significantly larger than the 1965-1985 slope. I am sure there's a simple test for that kind of structural break.

I think visual inspection suggests an uptick for "Jerry Garcia" as well, but there I'd really like to see the statistic. There's a substantive point that becomes an inferential point: The Grateful Dead was massively more popular (as measured by appearances in printed materials, and probably on any other sensible measure) than Jerry Garcia, per se. We know this. But, in books, it's about a 10x difference by the end, with the spread especially increasing 1986 and forward (i.e., post "Touch of Grey"). I'd hypothesize (call it H20140607c) that the two phrases co-appear more robustly in the later period, i.e., that Garcia is partly subsumed under the GD behemoth. That'd be appropriate.

The inferential point is that we can't really tell about the Garcia curve through visual inspection, because there's no way to set a separate vertical axis, which we need (per the substantive point I just made). So, here's just "Jerry Garcia":
Figure xxx. Google Unigram: "Jerry Garcia", 1965-1995

I think the answer is that, yes, there's a 1986 and post uptick, but, again, I'd like to run the statistic. In the meantime, pictures are fun.

Garcia and Marley

At some point I will write up Garcia's engagements with reggae. It's an interesting story, really revelatory.

In the meantime, on a lark, I played with Google Ngram for these two. Ngrams are a very neat tool.

Figure xxx. Google Bigram: Bob Marley and Jerry Garcia, 1965-1981

The vertical is the percentage of all consecutive two-word phrases in English language books from the given year, digitized by Google (all of them, pretty much, by the 1970s), comprised by the respect phrases "Jerry Garcia" and "Bob Marley".

This metric is good to compare over time appearance of the phrase (of N components, hence Ngram) (look at the sharp Marley trajectory to his passing, and Garcia's relative stability to this point).  Hypothesis: "Grateful Dead" will reveal this same kind of trend as Garcia; both will spike up 1986ff.

But it's also good to compare cross-sectionally, i.e., Garcia and Marley. Very simply, the picture says that Garcia was more popular earlier in this series, their stardom paths crossed in 1973, and Marley soared to greater fame until his death, while Garcia's level was established around 1973 and stayed steady during the rest of the period to 1981.