Economists, like other scientists and social scientists, observe and analyze behaviour and events. Economists are concerned primarily with the economic causes and consequences of what they observe. They want to understand an extensive range of human experience, including: money, government finances, industrial production, household consumption, inequality in income distribution, war, monopoly power, professional and amateur sports, pollution, marriage, music, art, and much more. Economists approach these issues using theories and models. To present, explain, illustrate and evaluate their theories and models they have developed a set of techniques or tools. These involve verbal descriptions and explanations, diagrams, algebraic equations, data tables and charts and statistical tests of economic relationships. This chapter covers some of these basic techniques of analysis.