Safety systems in aerospace, industrial, and critical sectors use more advanced methodologies than do web developers, and are typically "better" engineers who tend to be familiar with tools and methodologies like debuggers, profilers, tracing, testing, symbolic execution, and (semi/)formal verification. People in low level engineering like kernel, driver, and/or performance engineering tend to be more familiar with such tools and approaches, but aren't as likely to employ as formal or conservative approaches. Security ginreenigne folks should be lumped in for good measure.