Purpose: The core objectives of this conducted research were threefold: first, to assess whether early-phase verification and validation (V&V)techniques, encompassing software design review, code review, and inspection, significantly contribute to defect prevention throughout the software development process; second, to evaluate the impact of these techniques on the efficiency of software development in terms of time, cost, and resource allocation; and third, to conduct a comprehensive comparative analysis between early-phase verification and validation (V&V)techniques and traditional post-development testing regarding their effectiveness in defect prevention and software quality improvement.
 Methodology: Employing an experimental approach, this study conducted case studies within Tanzanian software development organizations. Data were meticulously gathered through surveys and interviews involving software professionals. Both quantitative and qualitative data were systematically analyzed to ensure data reliability and ethical considerations.
 Findings: The research findings indicate that early-phase verification and validation (V&V) techniques shine as powerful tools for defect prevention, leading to a substantial reduction in defect counts and elevating software quality metrics, such as reliability and user satisfaction. Notably, these techniques demonstrated a favorable impact on software development efficiency by shortening development cycles and curtailing costs. When compared to traditional post-development testing, early-phase verification and validation (V&V) techniques consistently outperformed in the realm of defect prevention and software quality enhancement.
 Unique Contribution to Theory, Practice and Policy: The study's outcomes underscore the transformative potential of early-phase verification &validation techniques, urging the software development industry to pivot from defect detection to defect prevention. The insights garnered here offer practical guidance for organizations aiming to streamline their software development processes, economize costs, and deliver top-notch software products that closely align with user expectations. While conducted in a Tanzanian context, these findings reverberate across the global software development landscape, underscoring the universal relevance of early-phase verification and validation (V&V) techniques as pivotal enablers of software quality assurance and operational efficiency.