Practices for IT development and quality assurance have foundations that extend much further back than the original invention of information technology.
The beginning lies with Walter Shewhart of Bell Labs who, in the 1930s, introduced the concept of plan-do-study-act (PSDA) to development processes. The method was innately cyclical, iteratively seeking to identify impediments, set plans to remove them, and then measure the impact of removal on outcomes. W. Edwards Deming greatly popularized these statistical control techniques through his work in post-war Japan, where they contributed significantly to revitalizing a shattered industrial economy.
