Derivation
variable: prefrest4 [decade estimate of previous village start] table[s]: tb_tbx, tb_tbxto2007, tbold_part1/2, tb_tbo, tb_tboto2007, tbold_control)
variable: prefrmm4 [month of previous village start] (table[s]: tb_tbx, tb_tbxto2007, tbold_part1/2, tb_tbo, tb_tboto2007, tbold_control)
variable: prefryear4 [year of previous village start] (table[s]: tb_tbx, tb_tbxto2007, tbold_part1/2, tb_tbo, tb_tboto2007, tbold_control)
recode prefrmm4 0=.
replace prefryear4=1895 if prefrest4==1
replace prefryear4=1905 if prefrest4==2
replace prefryear4=1915 if prefrest4==3
replace prefryear4=1925 if prefrest4==4
replace prefryear4=1935 if prefrest4==5
replace prefryear4=1945 if prefrest4==6
replace prefryear4=1955 if prefrest4==7
replace prefryear4=1965 if prefrest4==8
replace prefryear4=1975 if prefrest4==9
replace prefryear4=1985 if prefrest4==10
replace prefryear4=1995 if prefrest4==11
replace prefryear4=1895 if prefrest4==12
replace prefryear4=1907 if prefrest4==13
replace prefryear4=1924 if prefrest4==14
replace prefryear4=1940 if prefrest4==15
replace prefryear4=1951 if prefrest4==16
replace prefryear4=1960 if prefrest4==17
replace prefryear4=1970 if prefrest4==18
recode prefryear4 9999=. 0=.
gen prefrdate4=mdy(prefrmm4,15,prefryear4) if prefrmm4~=. & prefryear4~=.
replace prefrdate4=mdy(6,15,prefryear4) if prefrmm4==. & prefryear4~=.
