* NOTE: You need to set the Stata working directory to the path
* where the data file is located.

set more off

clear
quietly infix               ///
  float   hwtsupp     1-10   ///
  byte    hflag       11-11  ///
  byte    spmpov      16-16  ///
  double  spmtotres   17-38  ///
  double  spmthresh   39-60  ///
  double  spmfamunit  61-68  ///
  float   wtsupp      69-78  ///
  byte    age         83-84  ///
  using "[your IPUMS data download with the variables above]"

replace hwtsupp   = hwtsupp   / 10000
replace wtsupp    = wtsupp    / 10000

format hwtsupp    %10.4f
format spmtotres  %22.0f
format spmthresh  %22.0f
format spmfamunit %8.0f
format wtsupp     %10.4f

label var hwtsupp   "Household weight, Supplement"
label var wtsupp    "Supplement Weight"

/* my code */

/* round weights so they work as SAS frequency weights, and divide by 2 because of 2014 CPS experimental redesign */
gen rhwtsupp = round(hwtsupp/2)
gen rwtsupp = round(wtsupp/2)

gen oneperfam = 0
bysort spmfamunit (age): replace oneperfam = 1 if _n==1
/* Now you can use oneperfam==1 to analyze family units instead of individuals.
   Because it's sorted by age within families, with onperfam 
   if age <18 then the family unit includes a child under 18 */

gen povneed = spmthresh-spmtotres /* amount needed to bring the unit above SPM poverty */

gen kidpovcat=0
replace kidpovcat=1 if age<18 & spmpov==1 /* separate poor-kid fams from everyone else */

egen surpluscat = cut(povneed) if spmpov==0, group(10) /* create deciles of non-poor family units */

/* to get surplus per family for non-poor families - just using the youngest person in each fam unit */
bysort surpluscat: sum povneed [fweight=rhwtsupp] if oneperfam==1

/* to get deficit for poor families with children - just using the youngest person in each fam unit */
sum povneed [fweight=rhwtsupp] if oneperfam==1 & kidpovcat==1

/* diagnostic */
list spmfamunit spmthresh spmtotres povneed spmpov age kidpovcat
sum povneed [fweight=rhwtsupp] if kidpovcat==1, det
sum povneed [fweight=rhwtsupp] if spmpov==0, det