where are the most errors introduced in software projects
Software bug Most bugs arise from mistakes and errors made in either a program's source code or its design, or in components and operating systems used by such programs. A few are caused by compilers producing incorrect code. A program that contains a large number of bugs, and/or bugs that seriously interfere with its functionality, is said to be buggy (defective). Bugs can trigger errors that may have ripple effects. Bugs may have subtle effects or cause the program to crash or freeze the computer. Other bugs qualify as security bugs and might, for example, enable a malicious user to bypass access controls in order to obtain unauthorized privileges.
Human Factors Analysis and Classification System HFACS is based in the "Swiss Cheese" model of human error[2] which looks at four levels of active errors and latent failures, including unsafe acts, preconditions for unsafe acts, unsafe supervision, and organizational influences.[1] It is a comprehensive human error framework, that folded Reason's ideas into the applied setting, defining 19 causal categories within four levels of human failure.[3]