Contents

We present here an analysis on the determinants of used cars in Turkey.

A regression model was estimated for each make by using a large set of explanatory variables. The dependent variable is defined in log form so that the coefficients of explanatory variables indicate the percentage change in price in response to changes in explanatory variables. The coefficient of the age variable (year) shows the expected percentage decrease in the price when the car gets one year older.

The Results tab summarizes the regression results. The bars show the estimated coefficients, and the orange dots +/- 2 standard deviations (the so-called “confidence interval”).


Theory

  • Utility [f]
    • Transportation service
      • Security, quality
    • Prestige
  • Cost [m]
    • Fuel
    • Maintenance
    • Tax
    • Insurance
    • Risks

Price is assumed to be equal to expected net utility.


pt = ∫tT(ft − mt)dt


Data


Data source


Variables

  • Make/brand (Renault, Volkswagen, Opel, Ford, Fiat, BMW, Tofas, Hyundai, Mercedes-benz, Toyota, Peugeot, Honda, Audi, Citroen, Skoda, Seat, Chevrolet, Volvo, Kia, Nissan, Dacia, Mazda, Lada)
    • Dropped (Lada, Chevrolet, Tofas)
  • Series (for Renault, Clio, Fluence, Megane, Twingo, …)
  • Model (for Megane, 1.4 Extreme, 1.4 T Color Edition, …)
  • Fuel (dizel, benzin, benzin-lpg)
  • Gear (automatic, semi-automatic, manual)
  • Sellect (owner, dealer)
  • Year (age, 2016 = 0)
  • km
  • Color (White or gray, others)
  • Engine size
  • Location (İstanbul, Ankara, others)
  • Ad size (number of characters)
  • Price

Descriptive statistics

Statistic N Mean St. Dev. Min Pctl(25) Pctl(75) Max
yil 242,395 2,006.973 6.885 1,967 2,003 2,012 2,016
km 242,395 129,381.900 82,300.270 1 61,000 186,000 499,999
fiyat 242,395 47,122.770 39,954.620 750 24,250 55,000 499,000
istanbul 242,395 0.263 0.440 0 0 1 1
ankara 242,395 0.115 0.320 0 0 0 1
engine.size 238,567 1,831.477 23,243.810 10.000 14.000 16.000 600,600.000
reklam 242,395 39.838 15.957 9 26 54 67
white 242,395 0.582 0.493 0 0 1 1
automatic 242,395 0.114 0.318 0 0 0 1
semiautomatic 242,395 0.222 0.416 0 0 0 1
owner 242,395 0.618 0.486 0 0 1 1
diesel 242,395 0.419 0.493 0 0 1 1
lpg 242,395 0.341 0.474 0 0 1 1

Model

  • Model:
    • log(fiyat) ~ seri + log(km) + white + seller + shift + fuel + istanbul + ankara + reklam + year + white:year + shift:year + fuel:year
  • year is car age (negative)
    • Coefficient of year shows annual change in used car prices
  • The model is estimated for each make
  • Cars older than 29 years are omitted

Descriptives


Results