APP_NEW = APP_RAW, updated from 1993:1-1996:1 using Gallup phone polls
APP_NEWP= APP_RAW*PARTY
ASSASSIN= dummy for Reagan assassination attempt
CBSNYT =  CBS/NYT macropartisanship, 1976:1--
DEM =     dummy for Democratic Presidency quarters
EVENTS =  MES event series
GALLUP =  MES macropartisanship, 1953:1-92:4
GALNEW =  GALLUP updated using Gallup phone series (adjusted)
1988:2-1996:4
GHB =     Bush dummy
GHB1 =    start of Bush administration
GRF =     Ford sequence
GRF1 =
GRFT =    Variable decaying geometrically with time during Ford's term
IKE =     Eisenhower sequence
IKET =
IRAN =
JEC =     Carter sequence
JEC1 =
JECT =
JFK =     Kennedy sequence
JFK1 =
JFKAPP =
JFKCON =
JFKT =
LAGPARES =lagged("political approval" * PARTY) [see MES 1989]
LAGPCON = lagged(MICS * PARTY)
LBJ =     Johnson sequence
LBJ1 =
LBJT =
MICS =    Michigan Index of Consumer Sentiment
MICSP =   MICS*PARTY
PARTY =   marker for party control of presidency, 1=DEM and 2=GOP
PEVENTS = EVENTS*PARTY   
PTY_APP = PARTY*APP_RAW
QUARTER = quarter during a given year
RESID =   [ignore this]
RMN1 =    Nixon sequence
RMNT =
RWR =     Reagan sequence
RWR1 =
RWRT =
TROOPS =  Vietnam troops (used by MES)
VIETNAM = Vietnam battle deaths (not used by MES)
WATERGATE = dummy variable for Watergate crisis
WXC =       Clinton sequence
WXC1 =
YEAR =     Year