Agile development's use of iterations and increments is analogous to accuracy and precision. In general, "accuracy refers to the difference between actual target and deviated target and precision refers to tightness of the cluster data" (iSixSigma, "Accuracy").
In the context of Agile, accuracy
measures the degree to which new features provide any value. Any feature that does not provide value misses the project goal and is therefore inaccurate. Iterations focus on the value of each delivery cycle. Short iterations permit the team to deliver value as soon as it becomes known. Precision
measures how much value the features provide. Small increments provide fast value to the customer and prevent waste associated with overproduction, overprocessing, and inventory.
There is always the risk of making false assumptions. To minimize the gap between an assumption and discovering the impact, Agilists employ a design concept called the Agile Safety Net
The first goal for the team is to satisfy the customer. So the team must first determine whether the customer is satisfied. The team has a chance to get direct feedback on customer satisfaction during the sprint review. If the customer is not satisfied, the team must focus their retrospective meeting on improving the product. The next step is the inspection of the product. The assumption is that the customer is satisfied; otherwise, the team would be primarily focused on satisfying the customer.
If there is anything wrong with the product, the team will inspect and adapt
. If the product is good and the customer is satisfied, the team may focus on the delivery process for the product. If the process is suboptimal, the team will inspect and adapt. The same principle applies also to process management, product management, and team organization. Finally, if the software conforms to the requirements, the team will focus on doing a better job with less work. This is the top-down inspect-and-adapt in the retrospective.
At any point in the project, if a team member recognizes that they are doing useless work, dealing with a bad process, using poor techniques or a suboptimal tool, or even working on a piece of the product that has low value, rather than continuing with the useless work, the team will inspect and adapt. The repercussion of any change to the level of customer satisfaction is being observed. This is a bottom-up optimization of the process. Combining all these inspect-and-adapt cycles is an Agile Safety Net, which serves the purpose of continuous improvement.
iSixSigma, "Accuracy," https://www.isixsigma.com/dictionary/accuracy/
iSixSigma, "7 Wastes of Lean," https://www.isixsigma.com/dictionary/7-wastes-of-lean/