Studies have shown that agile methodologies shorten the software development cycle. Naturally, many assume that agile is all about speed. This is quite far from the truth.
What's the usual cause of delay in software projects? Quality. Or more accurately- lack of it. For example:
• Poor quality planning leads to project delays.
• Poor quality requirements, leads to poor implementation
• Poor quality implementation leads to defects which leads to delays
• Poor quality testing, leads to disaster
Agile methods infuse an intense focus on quality at all these levels.
• Planning is kept simple and straightforward to achieve sprint goals. Usually, the entire team participates in planning.
• Requirements are reviewed by all stakeholders and are kept minimal to achieve business value. The focus on business value ensures that only the “Minimal Marketable Features” make it to the sprint. Good requirements ensure that minimal code is written. We all know that the highest quality code is the code that isn’t written.
• Peer reviews, pair programming and Test Driven Development results in higher implementation quality.
• Quality is baked in at all levels. QA focuses on preventing defects rather than finding them.
A team that follows all this rigor will actually be writing fewer lines of code per day than other teams. Per conventional measurements, these teams are slower! However, the quality of the artifacts (all artifacts – not just the code) is much higher because it receives intense scrutiny. Enforcing quality at all levels has a happy side effect of speeding up projects. If you want to deliver more, and if you want to deliver it faster - slow down and focus on quality.
That's the essence of Agile methodologies.