Some days I'm really frustrated by people holding opinions in the face of experiments and data showing the opposite. It's one thing to say that the experiment isn't valid (and then please say why you think so), it's another to misread it entirely.
I'll be the first to admit that experiments around things like TDD are hard, but Medium posts like this one don't even attempt to look at the literature. blog.usejournal.com/lean-testing-o…
To inject some data into the discussion, sciencedirect.com/science/articl… is a good survey on the research on #TDD through 2014.
A table from that paper. Ignoring productivity (which I partially attribute to inexperience or poor training), everything else is in favor of #TDD (these are the "high rigor/high relevance" studies). 
Even the "low relevance" (but stil "high rigor") studies indicate that you are pretty likely to do better, and possibly no difference, so why not do #TDD?
And btw, "relevance" here indicates whether it was in an industrial or industrial-like setting, vs. a lab.
And, as studies like this mention, most empirical studies "tend to neglect whether the subjects possess the necessary skills to apply #TDD." So with more/better training in this complex skill, folks could do even better! sciencedirect.com/science/articl…
This study is interesting, in that it's qualitative/ethnographic and highlights difficulties in doing #TDD, e.g., it's not test-first that's hard, it's "switching from a plan-intensive mindset to a lightweight and flexible one"
sciencedirect.com/science/articl…
sciencedirect.com/science/articl…
Just doing the tests first, in other words, is the easy part, but if you've already fully mapped out and planned the implementation in your head, you're not really doing #TDD, you're just doing Test-First.
The study also shows that when learning #TDD, you need to also be learning Refactoring, otherwise you're not getting the real benefit of your new-found knowledge about the code and applying that knowledge by refactoring.
The conclusions are unsurprising to those who teach #TDD.
I discount the "it takes more time to do TDD" or "lower productivity" results in these papers because of things like "the increase in time [is] attributed to the usage of the TDD practice, as subjectively estimated by management." Estimated. By management.
@threadreaderapp unroll
