added results

NEED/README.md

@@ -9,6 +9,8 @@ http://discover.ukdataservice.ac.uk/catalogue/?sn=7518
 * Notes:
 * This dataset is a sample of just over 4 million households which have had an Energy Performance Certificate from the full NEED 'all dwellings' dataset
 * Is this all those who have had an EPC or a random sample of all those who've had an EPC?
-* Sample bias is unkown - which kinds of dwellings have an EPC?
+* Sample bias is unknown - which kinds of dwellings have an EPC?
 * Gcons<year>valid variable has undefined labels: G, L, M = ? Presumably 0 = off gas & V = valid?
 * ideally DECC should set missing to -99 to aid re-coding and avoid unpleasant surprises in naive analysis!
+
+UPRN = unique property reference = linkage mechanism
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