Just over a year ago the Ergonomics Society changed its name to the Institute of Ergonomics and Human Factors, in recognition (among other things) of the discrepancy between the growing range of interests within the organisation and the somewhat narrower perception of the term “ergonomics” to the world outside. There are many people who feel passionately about such terminology, and will argue quite strongly that it is perceptions that we should be changing, rather than our own identity. On the other hand, there are those who think that it is quite right that organisations should evolve to reflect the changing world, and that names and labels should not be thought of as sacrosanct.
But the purpose of this post is not to enter that debate. Instead, it is to test some of the assumptions about the usage of these terms, and see if they really hold true. This task is made somewhat easier by the recent launch of the Google Books Ngram Viewer, which gives us a unique insight into the usage of terminology across a range of publications, time periods and corpora (i.e. geographically-based collections). Google Books claims to have scanned over 10% of all books ever published, providing data on the occurrence of phrases up to five words in length from 1400 through to the present day.
For example, I had assumed (wrongly, as it turns out) that the term ergonomics was more prevalent this side of the Atlantic, and conversely that human factors was the dominant term on the other. This is a crucial point, as it underpinned the notion (in my mind, at least) that by adopting the term human factors we would better articulate our identity and mission to a global audience. (Indeed, by changing the name that outcome may still hold true, but evidently not for the reasons I’d assumed.)
So let’s look at the data. First, let’s see how often the terms “ergonomics”, “human factors” and “user experience” appear in all the English books indexed by Google, from 1950 to date. I have included the third term partially as it reflects my own personal interests (being by far the dominant term in the development of digital interactive products, e.g. web, software, mobile, and so on), and partially as a reflection of its growing acceptance in wider UCD circles (such as official standards documentation).
As I expected, user experience took off in the late 1990’s and continues on an upward trend. But what I didn’t anticipate is that ergonomics continues on an upward trend too, whilst usage of the term human factors actually appears to be declining from about 1990 onwards. This was certainly unexpected. So let’s check whether a geographic effect is at play: is this true of books published on both sides of the Atlantic? If we look at just those published in GB, then we see that user experience continues to rise, as expected, but both ergonomics and human factors start to fall from around 2000 onwards (with ergonomics entering a particularly steep decline):
Conversely, if we look at just books published in the US, then all 3 show a strong upward trend, and contrary to my own expectations, ergonomics is actually the dominant term over the last decade and a half:
The contrast between the US & GB trends is puzzling – why are ergonomics and human factors in such steep decline in GB when they are rising in the US? There must be further factors at play. Unfortunately, Google Books does not allow us to formulate queries such as “show me occurrences of these terms in all corpora except this one” (i.e. to see what the global trend is outside of either US or GB). Note also that the y-axis shows only percentages, so it is not possible to establish a baseline by which we can compare the absolute figures for different corpora.
So let’s try a different analysis. If Google Books represents the “supply” side, i.e. content creation, what is the corresponding picture from the “demand” side, i.e. the content consumption? For this we can use Google Trends, which allows us to see how often certain topics have been searched for on Google over time (and also how frequently these topics have appeared in Google News stories). Applying the same query to Google Trends produces the following result, with the y-axis showing the average worldwide traffic for all three terms normalised by the dominant term (ergonomics), and the x-axis showing the time period for which data is available:
Evidently, ergonomics is still the dominant term, but both this and human factors are in decline throughout the time period (note also the seasonal spikes at the end of each calendar year). User experience appears stable and dominates the Google News content, but it is hard to conclude more without being able to magnify the scale or probe further.
As a final datum, we should of course consider how frequently the various terms appear in the Google index itself (i.e. across the Internet). Would the patterns from Google Books be reflected across the web in general? Querying Google with each term in turn returns the following results:
- Ergonomics 6,110,000 results
- “Human factors” 2,350,000 results
- “User experience” 14,900,000 results
So, what can we conclude from all this? My personal feeling is that these investigations present many more questions than answers at this stage, so any conclusions we can draw thus far should be tentative at best. That said, the data would appear to suggest the following:
- The assumption that human factors is the dominant term in the US no longer appears to be true (at least, not for the last decade and a half)
- Usage of human factors appears to be declining globally, while both ergonomics and user experience continue to rise
- Both ergonomics and human factors have risen in the US over the last decade, but fallen in GB
- From a “demand” perspective, both ergonomics and human factors appear to have steadily declined over the time period for which data is available
- User experience is by far the dominant term across the Internet in general
Over the next few days I’ll be thinking about further ways to explore or validate the above observations. In the meantime, if you want to suggest any extensions or observations of your own, just drop me a line either here by email.