Derivation
variable: prefrest2 [decade estimate of previous village start] table[s]: tb_tbx, tb_tbxto2007, tbold_part1/2, tb_tbo, tb_tboto2007, tbold_control)
variable: prefrmm2 [month of previous village start] (table[s]: tb_tbx, tb_tbxto2007, tbold_part1/2, tb_tbo, tb_tboto2007, tbold_control)
variable: prefryear2 [year of previous village start] (table[s]: tb_tbx, tb_tbxto2007, tbold_part1/2, tb_tbo, tb_tboto2007, tbold_control)
recode prefrmm2 0=1
replace prefryear2=1895 if prefrest2==1
replace prefryear2=1905 if prefrest2==2
replace prefryear2=1915 if prefrest2==3
replace prefryear2=1925 if prefrest2==4
replace prefryear2=1935 if prefrest2==5
replace prefryear2=1945 if prefrest2==6
replace prefryear2=1955 if prefrest2==7
replace prefryear2=1965 if prefrest2==8
replace prefryear2=1975 if prefrest2==9
replace prefryear2=1985 if prefrest2==10
replace prefryear2=1995 if prefrest2==11
replace prefryear2=1895 if prefrest2==12
replace prefryear2=1907 if prefrest2==13
replace prefryear2=1924 if prefrest2==14
replace prefryear2=1940 if prefrest2==15
replace prefryear2=1951 if prefrest2==16
replace prefryear2=1960 if prefrest2==17
replace prefryear2=1970 if prefrest2==18
recode prefryear2 9999=. 0=.
gen prefrdate2=mdy(prefrmm2,15,prefryear2) if prefrmm2~=. & prefryear2~=.
replace prefrdate2=mdy(6,15,prefryear2) if prefrmm2==. & prefryear2~=.
