Asian Journal of Education and Social Studies

Consumer spending behavior is shaped by the interplay of prices, total expenditure, and budget allocation across goods. Demand system approaches and Engel-curve-based frameworks formalize how consumption patterns shift as households move along the income distribution and face changes in relative prices, and they provide an empirical basis for studying substitution and reallocation effects across broad consumption categories. Understanding how Philippine households adjust their consumption when prices change is essential for designing effective tax, subsidy, and social protection policies, especially in a context of recurring food and energy price volatility. This structured literature review synthesizes empirical and conceptual research on price elasticity and consumer spending behavior, with a focus on evidence relevant to the Philippines and complementary insights from international demand and behavioral literatures. The review highlights how food demand responsiveness differs across rural and urban households, income groups, and demographic profiles, and how “necessities” such as staple foods often show limited sensitivity to price changes compared with higher-value foods. It also consolidates evidence from Philippine sin-tax research demonstrating that price and tax reforms can shape smoking behavior through heterogeneous pathways, including cessation, downtrading, and cost-minimization strategies. Across domains, a central theme is that observed spending responses reflect both standard substitution and income effects, as well as broader mechanisms—quality substitution, brand switching, informal market use, and salience-driven reactions to taxes and posted prices. Methodologically, the review discusses the strengths and limitations of commonly used demand-system approaches applied to household expenditure surveys, including challenges in price measurement and identification. The paper concludes by outlining policy-relevant implications for nutrition-sensitive pricing, excise-tax design, and targeted compensation measures, while emphasizing research gaps such as stronger regional price measurement, dynamic adjustment modeling, and better integration of behavioral mechanisms into elasticity estimation for the Philippine setting. The review underscores that observed spending responses can reflect not only standard substitution and income effects but also quality substitution, channel switching, and salience-driven reactions to taxes and price presentation. The policy significance is clear: effective design of taxes, subsidies, and compensatory programs requires elasticity estimates that are interpreted with heterogeneity, measurement limitations, and behavioral mechanisms in mind.