220 likes | 507 Views
Econometric Analysis of Panel Data. Fixed Effects and Random Effects: Extensions Time-invariant Variables Autocorrelation Two-way Effects Nested Random Effects. Time Invariant Variables. The Model Fixed Effects
E N D
Econometric Analysis of Panel Data • Fixed Effects and Random Effects: Extensions • Time-invariant Variables • Autocorrelation • Two-way Effects • Nested Random Effects
Time Invariant Variables • The Model • Fixed Effects • b2 can not be identified, thus the individual effects ui can not be estimated.
Time Invariant Variables • Two-Step Approach
Time Invariant Variables • Random Effects • Mundlak’s Approach • Random effects model including group means
Example: Returns to Schooling Cornwell and Rupert Model (1988) Data (575 individuals over 7 ears) Dependent Variable yit: LWAGE = log of wage Explanatory Variables xit: Time-Variant Variables x1it: EXP = work experienceWKS = weeks workedOCC = occupation, 1 if blue collar, IND = 1 if manufacturing industrySOUTH = 1 if resides in southSMSA = 1 if resides in a city (SMSA)MS = 1 if marriedUNION = 1 if wage set by union contract Time-Invariant Variables x2i: ED = years of educationFEM = 1 if femaleBLK = 1 if individual is black
Autocorrelation • AR(1) • Assumptions
Autocorrelation • AR(1) Model Estimation (Paris-Winsten) • Begin with r=0, estimate the model • Transform variables according
Autocorrelation • Estimate the transformed model • Iterate until converges
Autocorrelation Notational Complexity with time lags in unbalanced panel data (Unbalanced unequal space panel data)
Autocorrelation • Hypothesis Testing • Modified Durbin-Watson Test Statistic (Bhargava, Franzini, Narendranathan, 1982) • LBI Test Statistic (Baltagi-Wu, 1999) • For unbalanced unequal spaced panel data
Example: Investment Demand • Grunfeld and Griliches [1960] • i = 10 firms: GM, CH, GE, WE, US, AF, DM, GY, UN, IBM; t = 20 years: 1935-1954 • Iit = Gross investment • Fit = Market value • Cit = Value of the stock of plant and equipment
Two Way Effects • The Model • Assumptions
Two-Way Effects • Dummy Variable Representation
Two-Way Effects Using one-way fixed effects or random effects model to estimate the dummy variable representation of two-way effects model.
Two-Way Effects • Two-Way Fixed Effects Model • Between Estimator • Within Estimator (Group Means Deviations)
Two-Way Effects • Two-Way Fixed Effects Model • OLS • Estimated Individual and Time Effects
Two-Way Effects • Two-Way Random Effects Model • Partial Group Means Deviations
Two-Way Effects • Two-Way Random Effects Model • Consistent estimates of qs are derived from: • se2 asym. var. of two-way fixed effects model • su2 asym. var. of between (individual) effects model or one-way fixed (individual) effects model • sv2 asym. var. of between (time) effects model or one-way fixed (time) effects model
Nested Random Effects • Three-Level Model • Assumptions • Balanced panel data only. Note: J=ii’ • Model Estimation • GLS • ML
Example: U. S. Productivity • The Model (Munnell [1988]) • Two-level model • Three-level model
Example: U. S. Productivity • Description • i=1,…,9 regions; j=Nj states • Gulf: AL, FL, LA, MO • Mid West: IL, IN, KY, MI, MN, OH, WI • Mid Atlantic: DE, MD, NJ, NY, PA, VA • Mountain: CO, ID, MT, ND, SD, WY • New England: CD, ME, MA, NH, RI, VT • South: GA, NC, SC, TN, WV • Southwest: AZ, NV, NM, TX, UT • Tornado Alley: AK, IA, KS, MS, NE, OK • West: CA, OR, WA • t=1970-1986 (17 years)
Example: U. S. Productivity • Productivity Data • 48 Continental U.S. States, 17 Years:1970-1986 • STATE = State name, • ST_ABB=State abbreviation, • YR =Year, 1970, . . . ,1986, • PCAP =Public capital, • HWY =Highway capital, • WATER =Water utility capital, • UTIL =Utility capital, • PC =Private capital, • GSP =Gross state product, • EMP =Employment,