Headscratches don’t really impact game development (after they finish a headscratch, you’ll notice a BIG set of bubbles…that is the bubbles they would have normally generated during the scratch). I am unsure if speed impacts the frequency of them.
Speed impacts the rate of tech and design bubbles. A low speed person might generate only a few bubbles during a development phase, while a high speed person will generate more.
A person’s tech/design skill will impact the size of bubbles that do get generated.
This has a multiplicative effect when combined with speed.
If you have high speed and low skill, you’ll generate a lot of small bubbles (5X3=15)
If you have a low speed and high skill, you’ll generate very few larger bubbles (3X5=15)
But if you have medium skill and medium speed, you’ll end up generating more total bubbles (4X4=16)
Keep in mind that every bubble has a % chance of turning into a bug, modified by the person’s experience level. High speed employees tend to make more bugs, especially if they are inexperienced.
When training your employees, don’t neglect speed. You’ll often find an employee makes far more bubbles after a single speed training than they do training design/tech, especially if their current speed is lower than their design/tech levels.
The problem with training speed is that it doesn’t help an employee reach any requirements for specialization training, since none of them care what their speed is.
Also pay attention to speed when hiring employees. You might think you’re building a balanced team by hiring one Tech focused employee and one design focused employee…but if the tech guy has a 295 speed and the design employee has a 135… you’re going to find your games flooded with tech bubbles. Great if you want action games, not so great if you were hoping to do RPGs.
Research is a far simpler value. The higher it is, the more research bubbles the employee generates when developing a game, a new engine or doing contract work. The only thing that modifies research points gained besides this skill is that doing new combo games nets you double the research point gain, all else being equal.