Table 1

Descriptive Statistics by the Full Sample, Counties with and without Purchase of Development Rights (PDR) Programs, 1949–1997, for Six Mid-Atlantic States

Variable	Definition of Variables	Full Sample (N = 2,602)		Counties without PDR Programs (N = 2,422)		Counties with PDR Programs (N = 184)
Variable	Definition of Variables	Mean	Std. Dev.	Mean	Std. Dev.	Mean	Std. Dev.
pcfland	Percentage change in farmland acres per agricultural census period	0.0735	0.1179	0.0761	0.1222	0.0412	0.0781
cfland	Change in farmland acres per agricultural census period	10,013	14,520	10,423	14,847	4,406	6,970
Explanatory Variables
fland	Total acres of farmland	142,005	106,974	144,169	108,803	110,436	73,547
medfinc	Median family income	29,885	11,076	28,683	10,112	46,039	10,847
met	= 1 if county was a metro area in 1950	0.2206	0.4147	0.2126	0.4093	0.3424	0.4758
nprofper	Profit per acre (sales minus expenses)	215. 2	461.1	209.7	1181.2	344.7	301.2
numf	Number of farms in county	981.1	895.1	994.6	906.8	782.4	698
pagffm	Percentage of residents employed in agriculture, forestry, fisheries, and mining	0.0997	0.1061	0.1046	0.1081	0.033	0.0266
medhval	Median housing value	61,128	33,495	57,249	29,131	113,757	44,033
phighsch	Percentage of adults with a high school education	0.4774	0.1760	0.4599	0.1690	0.708	0.074
phoffw	Percentage of operators working 100 + days off the farm	0.4045	0.1041	0.4023	0.1057	0.4313	0.0764
poppera	Population per acre	0.5514	1.701	0.5599	1.850	0.7319	0.7936
pfulln	Percentage of operators who own all of the land they farm	0.6725	0.1184	0.6766	0.1203	0.6214	0.0736
presprog	= 1 if a county has at least 1 acre of farmland enrolled in a PDR program	0.071	0.256	0	0	1	0

Source: U.S. censuses of agriculture (1949–1997); U.S. censuses of population and housing (1950–2000); AFT 2008, 2009; primary data collection from state and local PDR programs in the Mid-Atlantic states.