125.785 Research Methods in Finance Seminar One Monday 17 July 1 Honest politicians make the other 95% look bad -- Mark Twain 2 Overview Administrative Issues – – – – Aims and Objectives Introduction – 3 Timetable Labs Textbook Assessment Eviews Readings: Chapters 1-3, Chapter 16 optional Administration The general format will be for 1st half – – – A 2 hour seminar A 2 hour lab in either CLQB4 or IIMS5/6 Finish approximately 7pm. Textbook is Studenmund Using Econometrics: A Practical Guide. 5th Ed. – 4 4th Edition can also be used. Assessment 1 Assignment Due September 1: 20% Quiz 1: 31 July (10%) Quiz 2: 14 August (10%) Quiz 3: To Be Advised (10%) – 5 Probably 28 August Web Support Web CT should be available for students In the interim, the following website also will have material: http://www.massey.ac.nz/~bjmoyle/mu/teach.html 6 Computer Labs Your user-name is your student ID Your password is your 4 digit pin number You will benefit from bringing – – 7 A floppy disk OR A USB drive (preferred) We will use Eviews for this section of the course Learning Objectives Develop your skills at estimating economic relationships. – – 8 This skill cannot be memorised from a textbook or lectures The textbook and seminars are to assist and guide you. Increase your familiarity with statistical software. Learning Outcome To give you a sufficient background that you can: – – 9 Attempt a research project with some of the skills you have learned; or Can progress on to advanced techniques used in financial econometrics without difficulty. It is impossible to teach you all the tools you might use in the constraints of this paper. The Unreliability of Textbooks This is an applied paper, not a theory paper. – – – – 10 Every data set you model, will have ‘different’ problems present. It is impossible to memorise all the permutations of problems that you will encounter. Skilled researchers are those with good problemsolving strategies, not recall of textbook stylised facts. Most of this skill must be developed with practical work. Introduction to Research A research project involves three stages – – – 11 Choosing a Topic Analysis Writing Report Choosing a Topic Ideally choose something you are interested in for motivation Make sure you can get enough data Make sure there is some substance to topic – – Not purely descriptive Not tautological (so obvious to be uninteresting). 12 E.g. does an increase in the number of bidders raise prices? Analysis Develop your theoretical model first – Specify the model – 13 What causes what? Hypothesise the effects you expect – May involve reading literature This must be done before you run any models Collect the data Analysis 2 Estimate the Equation – Document the results – 14 This should take the least amount of effort There must be enough information given, that someone else could replicate your results. Report Writing This is an important step – – 15 The purpose of research is often to generate information for a decision-maker. Hopefully, a manager or policy-maker could read your report and learn something new. A box of computer printouts, neither informs nor impresses. Report Writing 2 A report should not gloss over or ignore results that you did not expect. – Keeping a research journal can assist – 16 It is a common mistake to not discuss results that contradict your prior beliefs. Record your hypotheses, regression results, statistical tests etc. Practical Advice Use common sense and economic theory – Ask the right questions – Sometimes regression problems are a consequence of the wrong specification Know the context – 17 E.g. Real variables should not be matched with nominal. Understand the problem, not just the statistics Practical Advice 2 Inspect the Data – Keep it sensibly simple – – Complexity is not ‘good’ for its own sake Consider Occam’s Razor. Look long and hard at your results – 18 Graphs or summary statistics can reveal missing variables, outliers or other anomalies. Does it make sense? You have to explain this to others. Practical Guide 3 Practice data-mining with care – Be prepared to compromise – – 19 Exhaustive experimentation to ‘get’ the ‘right’ results shows you’re biased… Trying to find the perfect model will drive you crazy. Real data tends to throw up intractable problems. Practical Guide 4 Do not confuse statistical significance with meaningful magnitude. – – Report a sensitivity analysis – 20 Trivial variables may have very small effects, but are highly significant. It is tempting to use statistical significance as a measure of a model’s performance. Do results vary of you change the sample period etc? Basic Stats We use statistical tools in this paper – – 21 But it is not a course in statistics We will estimate the value of many parameters E.g. – A mean (average) A regression coefficient We signal our uncertainty about the parameter with a type of ‘spread’. E.g. – – Variance Standard Deviation These uncertainty measures form the basis of statistical tests. Recap The main difference between statistics and other maths, is answers will have 2 dimensions In normal algebra, variables combine to produce an explicit solution. In statistics, we think in 2 dimensions – – 22 What we think the value of something is How confident we are in that estimate Correlation Quantifies the relationship between 2 variables. -1 ≤ r ≤ 1 Correlations imply – – 23 Relationships or associations General tendencies Correlations do not prove causality Correlations can be shown graphically Correlation between GDP and G 25000 CGDP 20000 CGDP 15000 10000 5000 0 0 24 10 20 30 40 CG 50 60 70 Regression Suppose we wanted to – – 25 Forecast prices for an asset. Determine causes of unemployment A regression “models” finance or economic data Regression Models can be used for several purposes. – – – Forecasting Testing hypotheses Detecting influential variables Simple OLS Model 26 We begin with the Ordinary Least Squares (OLS) regression model This generates a ‘straight line’ between 2 variables. The line ‘approximates’ the relationship between the two variables The variables are – – Dependent (Y) Independent or explanatory (X). Regression Example Y is GDP per capita X is Govt spending We ‘explain’ Y in terms of X We can estimate Y if we know – – 27 Intercept of line- constant Slope of line Note on Regression Researchers can (potentially) use many different regression techniques. OLS is a convenient starting point. – – 28 But not all regression models use least-squares methods. If certain assumptions are met, OLS is the best method to use. Intuition OLS is based on Cartesian Geometry. – – – 29 The line we estimate (with intercept and slope), comes closer to all the observations than any other line. We minimise the (sum of) distance between the line and the observations (squared). This is an idea that draws on geometry. As a minimisation problem, it can be readily solved with differential calculus. Eviews Eviews is a popular (and powerful) econometrics program. – 30 It is the software most students use for their graduate research reports Where menu to estimate equations is located 31 Equation Estimation Menu 32 Dependent Variable Explanatory Variable Constant 33 Output 34 Readings Studenmund – – WebCT – 35 Chapter 16 Statistical Principles Chapter 1-3 Guide to Eviews- Introduction