Coding for Applied Economists

Challenge 7 (Problem Solving)

For this challenge you are going to take the plot_dataset and create a household-level analysis dataset (one row per hh_id_merge). This is essentially the “goal problem” from this week, but here you will carry it to completion. In building the household-level data set, you are not allowed to use collapse.

1. Plan first (problem decomposition in your .do file). Before writing real code, create a section where you plan the solution using headings and comments only.

  • Restate the problem in your own words
  • Identify inputs/outputs
  • Break into steps (load → construct variables → aggregate/tag → check uniqueness → analysis → graphs → save)

2. Build the household dataset.

  • Start by dropping all observations that are not maize
  • Instead of using collapse, use egen to compute household-level statistics for the following: - hh_id_merge - mean_yield = mean of plot-level yield_USD - tot_labor = sum of total_labor_days - tot_fert = sum of nitrogen_kg - n_plots = count of plots per household - any_irrig = 1 if household has any plot with irrigated==1, else 0
  • Label each variable
  • Tag one observation per household using the tag function
  • Use keep if to keep one row per household. How many observations are now in the data set?

3. Check that following and include *** comments recording the mean of each variable and the number of irrigated plots:

  • Confirm the dataset is one row per household: isid hh_id_merge
  • Summarize mean_yield, tot_labor, tot_fert, n_plots
  • Tabulate any_irrig

4. Run the regressions reg mean_yield tot_labor tot_fert any_irrig. Add *** comments that report:

  • The sign of each coefficient
  • One sentence interpreting the coefficient on any_irrig

5. Create two graphs.

  • A twoway scatter plot of household mean yield (y-axis) vs total fertilizer (x-axis). Overlay a linear fit (lfit) to the data and provide informative axis titles and a legend.
  • Create a bar chart of mean household yield by irrigation status (over). Bars are for any_irrig==0 and any_irrig==1 and the y-axis should be the mean of mean_yield.