Distinguish between the root cause of a defect and its effects

All defects have their root causes, i.e. the conditions and / or earlier actions that led to the defect.

Therefore, the search for the root causes and their analysis is the key to a significant reduction in the number of defects provoked by them in the future.

For example, if the program incorrectly calculates the ratio of ingredients for the manufacture of a product, then this enterprise may suffer losses, both due to excessive overspending of ingredients, and due to the production of unsaleable products.

The effect is the overspending of ingredients, as well as the release of unusable products.

The defect is an incorrect calculation algorithm that was created under the influence of the root causes.

The root cause of this defect can be either an error in the requirements, or a programmer's misunderstanding of the correct calculation algorithm, or an error caused by the working conditions (too noisy in the room, too much work and not enough time, or due to other root causes), or something else. To avoid the appearance of defects and the manifestation of their effects, it is necessary to identify the root causes as early as possible and try to exclude their impact.