34 MAIRE NI BHROLCHAIN study of e.g.the structure of atoms and molecules.In this case,we would not know wby such children But the emotive charge is probably especially fare less well than others. pronounced in relation to family matters.Children's Version B2 seems initially to be the question that response to divorce is embedded in broader social-we might ask if the subject-matter lent itself to political controversy,but the focus of the present experiment,which it clearly does not.But B2 side- paper is on the scientific and professional aspects. steps the true experimental question.An experi- What is the evidence?How has it been interpreted? mental question would be posed in factual rather Is such interpretation valid?If not,why not?Why is than counterfactual terms:Do children in two- evidence on the question over-interpreted?What parent families suffer long-term disadvantage can we do to move up a gear,in a scientific sense? wben their families are subjected to divorce?' Phrased thus,the question is absurd.Divorce is undertaken voluntarily by one or both parents The Question at Issue and cannot be imposed on both parties except in rare circumstances (e.g.the case of the Egypt- The question 'Does parental divorce have adverse ian couple faced with coercion by Islamic law to long-term effects on children?'is less straight-divorce because of what was seen as the apostasy forward than it appears.2 It can be understood in at of the husband).It is impossible to assign least two ways: families at random to a divorce treatment'and a A-Aggregate-level:Does the level of divorce in a 'stable family treatment,and certainly not a society influence the long-term welfare or well- bereavement treatment,holding relevant vari- being of children in that society? ables constant,and examine the 'effects'on the B-Individual-level:Does the divorce of their par- children in the long term.Nevertheless,a weak ents adversely affect the children of the marriage version of this idea probably assails our thinking in the long term? when we attempt to puzzle through the un- By and large,it is the individual-level version of the certainties surrounding the issue.A natural way question that has been the subject of both academic of trying to get an intuitive grasp of the question and public debate although elements of the aggre-is by asking what would happen to the children gate issue may also be influencing thinking and of such-and-such a family with whom we are comment.3 The individual-level question is the pri-acquainted,usually a happy one,if the parents mary focus of this paper and might be specified in were to separate.Such thinking misleads,how- several ways,only one of them correct:+ ever,because divorcing couples are not a B1:In the long term,do children in two-parent random selection of married couples,and so our families fare better than those in one-parent mental experiment will probably be biased.Our families? attempts to think intuitively would be better B2:Womld children in two-parent families suffer served if we were to imagine the hypothetical adverse outcomes in the long term if their par-costs and benefits to cbildren in families at genuine ents were to divorce? risk of divorce,that is,those experiencing the kinds of diff- B3:Would the children of those couples who do culties that usually precede marital breakdown. divorce suffer fewer adverse outcomes in the Question B3 is,in my view,the true question at long term if their parents were to stay together?issue.Strictly speaking it cannot be answered in Question Bl appears to be the one that many com-this form since it requires that the same individuals mentators have in mind.Although the correct follow two mutually exclusive paths through the life- answer to this question appears to have been 'yes,cycle and that the associated outcomes be observed. this does not mean that divorce adversely affects The best initial approximation to the implied com- children,since the question in this form is merely parison is by statistical means.There are two about a correlation.5 Any difference in outcomes components to the comparison:first,specifying may be the result of factors (that give rise to or the outcome measure and second,approximating impede parental divorce that(b)would have been to the randomization that would take place experi- present in any case had the divorce not occurred. mentally.Ideally a comparison should be made of               7                 )4                              ?    @ $     @ !       @ !     @ ?          @ ?              @     5    2
        3   @4          9 !         A + > + A
         B              @ 7 > ! A
         3         @ 7                  /                         B  "   = 5                           AC 7%A !                @ 79A      3                @ 7=A           3                    @ D   7%               +                24        3                 - + 3            #*           #*               !       "            ; 79             "    /            E 7 79            +                     A 2       3           /    @4 8         
   "                          #               !                 * !          2   4   2     4      2   4           23 4        <   "         "       00              +                   "                                    "                               1      "                              !   "   "   #    !  $        !% D   7=                  "                                      5                  5       A               0     "     !