from the g.e. 2011 and 2015 election results,it is clear most of the opposition stronghold are in the east where i live,mainly in aljunied,east coast,marine parade,hougang etc......any coincident?the east side seems to be a pretty well developed area and boast a strong range of the best secondary schools and jcs.....population here tends to be more refined and well off and highly educated than the western peasant slumlands.
PAP strongholds are namely in jurong,west coast,pioneer,ang moh kio,chua chu kang,bukit batok.....