My guess is some high-paying jobs that were called "Data Scientist" 3 years ago are now called "Data Engineer" and "Machine Learning Engineer", hence the average salary for jobs still called "Data Scientist" goes down a little.
Note the actual percent depends on how you measure it.
In addition to that, I think some lower-paying roles that used to be analysts or BI specialists are increasingly being called Data Scientists. My guess would be if you controlled for skills and job responsibilities you’d see increases.
Second, this is data scraped from Australian job listings. So the title should probably reflect that.
Lastly, this data seems a little odd. You’ve got month-to-month swings of 20% or more happening here. This data source seems extremely noisy and I don’t think there’s anything you can reliably say about a trend here.
I think others in the comments have pointed out why, if it were real, you might see this overall trend and why it doesn’t mean salaries for the same role are falling.
This looks like a fun side project, but I would be careful reading anything into the results.
Noted. I'll incorporate this feedback in the next edition (circa end 2022 or early 2023).
The large month to month swings are because the Australian labour market isn't so big, so even a single employer's hiring spree can significantly affect the number of listings in a given month. There are seasonal effects in there too of course. It's volatile data.
I did a quick mock up using a general additive model, which I think's a better fit. I'll use it next edition: https://i.imgur.com/7oTn9Oq.png
My guess is some high-paying jobs that were called "Data Scientist" 3 years ago are now called "Data Engineer" and "Machine Learning Engineer", hence the average salary for jobs still called "Data Scientist" goes down a little.
Note the actual percent depends on how you measure it.
Full source/data/code: https://www.kaggle.com/nomilk/data-science-language-and-job-...