Editing Simultaneous equations model (section)

== Applications in social science ==
Across fields and disciplines simultaneous equation models are applied to various observational phenomena. These equations are applied when phenomena are assumed to be reciprocally causal. The classic example is supply and demand in [[economics]]. In other disciplines there are examples such as candidate evaluations and party identification<ref>{{Cite journal|last1=Page|first1=Benjamin I.|last2=Jones|first2=Calvin C.|date=1979-12-01|title=Reciprocal Effects of Policy Preferences, Party Loyalties and the Vote|journal=American Political Science Review|volume=73|issue=4|pages=1071–1089|doi=10.2307/1953990|issn=0003-0554|jstor=1953990|s2cid=144984371 }}</ref> or public opinion and social policy in [[political science]];<ref>{{Cite journal|last=Wlezien|first=Christopher|date=1995-01-01|title=The Public as Thermostat: Dynamics of Preferences for Spending|jstor=2111666|journal=American Journal of Political Science|volume=39|issue=4|pages=981–1000|doi=10.2307/2111666}}</ref><ref>{{Cite journal|last=Breznau|first=Nate|date=2016-07-01|title=Positive Returns and Equilibrium: Simultaneous Feedback Between Public Opinion and Social Policy|journal=Policy Studies Journal|volume=45|issue=4|language=en|pages=583–612|doi=10.1111/psj.12171|issn=1541-0072|url=http://osf.io/wt376/}}</ref> road investment and travel demand in geography;<ref>{{Cite journal|last1=Xie|first1=F.|last2=Levinson|first2=D.|date=2010-05-01|title=How streetcars shaped suburbanization: a Granger causality analysis of land use and transit in the Twin Cities|journal=Journal of Economic Geography|volume=10|issue=3|pages=453–470|doi=10.1093/jeg/lbp031|issn=1468-2702|hdl=11299/179996|hdl-access=free}}</ref> and educational attainment and parenthood entry in [[sociology]] or [[demography]].<ref>{{Cite journal|last=Marini|first=Margaret Mooney|date=1984-01-01|title=Women's Educational Attainment and the Timing of Entry into Parenthood|jstor=2095464|journal=American Sociological Review|volume=49|issue=4|pages=491–511|doi=10.2307/2095464}}</ref> The simultaneous equation model requires a theory of reciprocal causality that includes special features if the causal effects are to be estimated as simultaneous feedback as opposed to one-sided 'blocks' of an equation where a researcher is interested in the causal effect of X on Y while holding the causal effect of Y on X constant, or when the researcher knows the exact amount of time it takes for each causal effect to take place, i.e., the length of the causal lags. Instead of lagged effects, simultaneous feedback means estimating the simultaneous and perpetual impact of X and Y on each other. This requires a theory that causal effects are simultaneous in time, or so complex that they appear to behave simultaneously; a common example are the moods of roommates.<ref>{{Cite journal|last1=Wong|first1=Chi-Sum|last2=Law|first2=Kenneth S.|date=1999-01-01|title=Testing Reciprocal Relations by Nonrecursive Structuralequation Models Using Cross-Sectional Data|journal=Organizational Research Methods|language=en|volume=2|issue=1|pages=69–87|doi=10.1177/109442819921005|s2cid=122284566 |issn=1094-4281}}</ref> To estimate simultaneous feedback models a theory of equilibrium is also necessary – that X and Y are in relatively steady states or are part of a system (society, market, classroom) that is in a relatively stable state.<ref>2013. “Reverse Arrow Dynamics: Feedback Loops and Formative Measurement.” In ''Structural Equation Modeling: A Second Course'', edited by [[Gregory R. Hancock]] and Ralph O. Mueller, 2nd ed., 41–79. Charlotte, NC: Information Age Publishing</ref>