Consider the impact of the project, not the size of the project.

A software architect might do ad hoc developing, or write up a limited test plan based on the risk analysis when project is not big enough to justify extensive coding.

Consider the impact of the project errors, not the size of the project.

Software developing goal is to detect problems in the work products. Software Coding focused in the product content and quality control after the fact. Software Developing activities are to develop and run test; check results are correct. 

Software developing has well defined technical goals; a history of saving the developers from greater evils; leverage to stop the show.

Quality planning involves identifying which quality standards are relevant to a project and determine how to satisfy them. Organizational planning is to identify, document and assign projects roles, responsibilities and reporting relationships. Project Plan Execution is carrying out the project plan by performing the activities included there in. Integrated Change Control is to coordinate changes across the entire project.

Quality Assurance involves evaluating overall project performance on a regular basis to provide confidence that the project will satisfy relevant quality standards. Quality Control is monitoring specific projects results to determine if they comply with relevant quality standards and identifying ways to eliminate causes of unsatisfactory performance.

QA processes should be balanced with productivity so as to keep bureaucracy from getting out of hand. 

Verification typically involves reviews and meetings to evaluate documents, plans, codes, requirements and specifications. 

Validation  involves actual testing and takes place after verifications are completed. A walkthrough is an informal meeting for evaluation or informal purposes.