Recent empirical studies that compared static and dynamic type systems on API usability showed in most case a positive impact of static type systems on developer productivity. But it is unclear how large this effect is in comparison to other factors. One obvious factor in programming experiments is tooling: It is commonly accepted that modern IDEs have a large positive impact on developers, although it is not clear what parts of modern IDEs are responsible for that. One possible, and for most developers obvious candidate is code completion. This paper describes a 2x2 randomized trial that compares JavaScript and Microsoft’s statically typed alternative TypeScript with and without code completion in MS Visual Studio. While the experiment showed (in correspondence to previous experiments) a large positive effect of the statically typed language TypeScript, the code completion effect is not only marginal, but also only close to significant. This seems to be an indicator that the effect of static type systems is larger than often assumed — at least in comparison to code completion.