In my experience, simply changing environments may cause an increase in productivity. Even if the new environment isn't strictly better, you still get a boost until you get acclimated. This might be crazy, but some sort of random rotation between various work environments might yield a sustained improvement in productivity.
There's the fairly well-established Hawthorne Effect[1] when applied to measuring productivity in others, but I'm not sure how well it would apply to self-analysis since you actually know the details of what you're studying.
Quoting:
Changing a variable usually increased productivity, even if the variable was just a change back to the original condition. However it is said that this is the natural process of the human being to adapt to the environment without knowing the objective of the experiment occurring.
Unless you're measuring against some concrete metric though, there's potential for misinterpreting a feeling of increased productivity vs actually achieving it. Also, you may be more motivated since you know you're measuring your output.
