少 MAIRE NI BHROLCHAIN primary studies in this meta-analysis has been exam-question.Some authors acknowledge that causal ined by Jameson(1996)to evaluate the quality of inference may not be justifiable,but most ignore information used in the meta-analysis.The studies this proviso in terminology and discussion.At face were found to be mainly below regional level in value this literature gives the impression that coverage,nearly half did not use probability sam- parental divorce caures children to experience a pling at any stage,most gave no details of response range of long-term disadvantageous outcomes and rate,and most used no statistical controls at all.it is routinely interpreted in this way.Furthermore Finally,the large majority(89 per cent)were cross- this conclusion often appears trouble-free,giving sectional in design,with only one having any ele- rise to few difficulties of method,data,or inference. ment of before and after'comparison.On this My view is that there are major difficulties ofall three evidence,the psychological literature on the subject kinds. has so many shortcomings that it can scarcely sup- Most existing studies make comparisons that are port an inference concerning an association poorly designed,and with inadequate sets of control between parental divorce and children's outcomes, variables.There is much duplication of data-sets. let alone inference as to a causal influence in this Most rely on data that are of poor quality in some regard.9 crucial respects and take no steps to eliminate poten- There are many studies of 'divorce effects'in the tial biases in the data.Regression coefficients are sociological and demographic literature that employ routinely interpreted as representing causal effects. large data-sets.These are the focus of interest here. Little attention is given to individual differences Many are cross-sectional,or use longitudinal data in either in the outcomes of interest or in the propen- a cross-sectional way.Some of the outcomes consid-sity to divorce.Findings at variance with the ered are measures of school attainment or of supposed adverse influence of parental divorce are behavioural or emotional adjustment prior to age sometimes overlooked.Finally,hypothesis testing 16.A large proportion relate to socio-demographic is weak.The divorce effects'literature shares these indicators in adolescence and young adulthood-deficiencies with much of the social science litera- staying on at school beyond the compulsory limit ture.But the problems are seen in high relief in and other measures of educational attainment, relation to divorce because there has been so much early cohabitation or marriage,early parenthood,apparent certainty about the issue in public debate. and the like.Most of these studies use some form To evaluate the evidence relevant to the causal of multiple regression,with child outcomes as connection between parental divorce and long- dependent variables,and with independent vari-term outcomes for children,those large sample stu- ables featuring family structure and anything from dies have been identified that meet the criteria one to many control variables.Measures of family specified in the preceding section:before and after structure differ greatly between studies,ranging studies-those beginning with a sample of child- from cross-sectional parental marital status,parents ren in intact two-parent families-that evaluate ever divorced before a given age,through to time-change in some outcome from before to after the varying indicators of family status.Some look at a divorce or,if not,an outcome that occurs unam- single outcome,others at a range of outcomes.biguously after separation,in which both pre- Where several outcomes are examined they are separation child and parental covariates,measured sometimes closely related.With some exceptions,a prior to separation,are controlled for.There are significant coefficient is usually found for family dis-many other studies of the subject that do not have ruption,and where type of disruption is given,the these characteristics and these have,on the whole, coefficient for divorce tends to be statistically signif-made a useful contribution in establishing a basic icant and that for widowhood not so.This is not so correlation between divorce and outcomes.Studies clear-cut in those few studies using dynamic analysis known to me as of mid-1999 that meet the criteria of family change (Wojtkiewicz,1993;Wu and specified number 10,one of which (Cherlin ef al., Martinson,1993;Wu,1996).With some exceptions,1991)employs two data sources,making 11 analyses regression coefficients are usually taken to reflect a in all.10 The data source on which each analysis is causal effect of family disruption on the outcome in based,together with sample size,children's ages,            H #%&&E*                 5                                                F   /  #'&   *               2   4  1           /                        4           B     & 5      2 3 4               5         6                                    /      %E +                  >                                  " 6                                          6        3                                       "              ?             ?       G                      G                   5                #?/ " 0 %&&=( ?  6  %&&=( ?  %&&E* ?      G     "  B    3                 "         /             +                                       F               G          6      / G      " 6     "                 5           6                   "               I G             3  J          3                  F        B         " F      " 5 2 3 4                 7                                  5                                             A       >              >                                                          5          /                                     "      %&&&         %:    #)    %&&%*       " %%    %: 5               0 4