Sir, - In David Gwynn Morgan's contribution in The Irish Times (April 30th) concerning the Des Hannafin appeal to the Supreme Court, he states: "This is a specialised question, namely, whether the Government's expenditure had materially affected the result of the referendum." In other words, did the £500,000 worth of advertising by the Government influence the referendum outcome, given that the "Yes" vote exceeded the "No" vote by only 9,000 in a total poll exceeding one million. (If some of the votes which were influenced by Government advertising came from the "No" side, then the Government could have succeeded in changing the outcome by influencing the voting decisions of less than 9,000 subject to a minimum of 4,500.)
David Gwynn Morgan's piece refers to one of the main arguments used by the State in the High Court hearing and accepted by the High Court judges. It is the argument based on the multiplicity of factors which influence voters' decisions. However, this argument was not fully addressed in the High Court. It is a problem frequently met with in economic research, or in any research based on actual life as distinct from controlled conditions in laboratories. The problem of a multiplicity of causative factors is often handled in real life research by the assumption, expressed succinctly in Latin as ceteris paribus - other things being equal (or unchanged).
Unless it can be shown that there is interaction between the influences on voting choice, it may be reasonably assumed that the influences are independent of each other. Then, one may theoretically consider the influence of Government expenditure on advertising on its own, other things being equal. It is reasonable to expect that Government advertising had a positive influence on votes favourable to the "Yes" outcome (though a comment by one judge in the High Court implied that a negative connection was possible!)
If the "coefficient" of Government expenditure on advertising or the number of "Yes" votes which (say) £100 of such expenditure influenced, exceeded 0.18, then it would appear that the outcome of the referendum was materially affected by Government advertising expenditure. Consultation with experts in the field of advertising would be desirable before judges could come to a safe conclusion on this question.
It is possible that there may have been some interaction between advertising by the Government and other influencing factors. For instance, Government spending may have led to a lower level of spending by promoters of the "Yes" vote. If it were true, then the effect of Government spending would be lessened. Likewise, its effect would be lessened if it generated increased spending by the promoters of the "No" vote, in an attempt to counteract the influence of the Government's advertising campaign.
However, it is more likely that the advertising budgets of the pro and anti groups were pretty well fixed in amounts and fully spent in the case of the "Yes" vote, and, in the case of the "No" side, could not have been increased to counter Government spending on advertising.
In conclusion, apart from the technical legal aspects of the case which David Gwynn Morgan has outlined in his article, he put his finger on the nub of the issue: will the Supreme Court decide that £500,000 worth of advertising had a material effect on the outcome of the referendum, "given the paper thin margin of the majority"? Or, did each £1,000 of Government advertising expenditure succeed in increasing the "Yes" vote by 18 votes, or even by somewhat less than that number? - Yours, etc.,
(Former lecturer in economics),
Lisieux,
Cork Road,
Mallow.