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volume 5
april 2002

A reconstruction of the original figures at age sixteen

 





Appendix 2 to: "Television violence is fully harmless"
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  As Johnson and his cowriters do not offer sufficient information, we can not reconstruct their original data for aggressive behavior at age sixteen for youths from "low income families" completely. Given the totals and subtotals of their tables, we here present some variants. The first one attributes relatively low scores for aggression to youths from low income families both in the category watching less than an hour and over three hours (see Table B):
 
poverty aggressive   daily hours television   total total
  behavior   less than 1   1 to 3   3 or more   at 16 at 22

+ +   1     5     10     16   32  
+ -   7     16     26     49   33  
  subtotal:     8     21     36     65   65

- +   4     82     57     143   166  
- -   76     283     140     499   476  
  subtotal:     80     365     197     642   642

  total:     88     386     233     707   707
  Table B: Reconstructed data describing the relation between low family income (poverty), daily hours of television at age fourteen and aggressive behavior at age sixteen — showing no significant correlations between poverty and aggression
  The figures in Table B conform to those in Table 6 in our main text. We suspect that the original data of the Children in the Community Study may have looked like this, as the correlation between "low family income" and "aggressive behavior" here is not significant. That could have been an important reason for the New York research group to impute the figures at age twenty-two into their data set for age sixteen. With the figures of Table B the variation in aggressive behavior mainly depends on the amount of "daily hours of television" which by itself explains 2.4% of variance in aggressive behavior. Table C below offers another option by attributing a relatively low score for aggressive behavior to youths from low income families in the category watching less than an hour and a relatively high score for youths from low income families spending over three hours on watching television on a daily base.
 
poverty aggressive   daily hours television   total total
  behavior   less than 1   1 to 3   3 or more   at 16 at 22

+ +   1     6     21     28   32  
+ -   7     15     15     37   33  
  subtotal:     8     21     36     65   65

- +   4     81     46     131   166  
- -   76     284     151     511   476  
  subtotal:     80     365     197     642   642

  total:     88     386     233     707   707
  Table C: Reconstructed data describing the relation between low family income (poverty), daily hours of television at age fourteen and aggressive behavior at age sixteen — showing significant correlations between low family income and aggressive behavior
  If the original data of the Children in the Community Study looked like this, the New York research group would not have needed to impute the figures at age twenty-two into their data. The results of an analysis of the figures in Table C ressemble those of the reconstructed data at age twenty-two. Together "low family income" and "daily televison time" here explain 4.4% of variance in "aggressive behavior". By themselves both "low family income" and "daily televison time" explain about 2% of variance. The remaining 0.5% of explained variance can be attributed to the interaction of "low family income" and "daily televison time". Theoretically, of course, we can think of other outcomes for the original data. Table D below attributes a relatively high score for aggressive behavior to youths from low income families in the category watching less than an hour and a relatively low score for youths from low income families spending over three hours on watching television on a daily base.
 
poverty aggressive   daily hours television   total total
  behavior   less than 1   1 to 3   3 or more   at 16 at 22

+ +   4     9     9     22   32  
+ -   4     12     27     43   33  
  subtotal:     8     21     36     65   65

- +   1     78     58     137   166  
- -   79     287     139     505   476  
  subtotal:     80     365     197     642   642

  total:     88     386     233     707   707
  Table D: Reconstructed data describing the relation between low family income (poverty), daily hours of television at age fourteen and aggressive behavior at age sixteen — showing no independent contribution of low family income to aggressive behavior
  It is highly unlikely that the original data of the Children in the Community Study looked like this. If so, the New York research group would have mutated their figures considerably by imputing those at age twenty-two. Though here "low family income" and "aggressive behavior" correlate significantly (r = .087, p < .05), the influence of "low family income" almost totally works by way of strengthening the amount of television time. Analysis of the figures in Table D results in 2.9% of variance explained in "aggressive behavior", for most of which (2.1%) "television time" is directly responsible. The remainder is due to the interaction of "low family income" and "television time". A last option is shown in Table E, attributing relatively high scores for aggression to youths from low income families both in the category watching less than an hour and over three hours:
 
poverty aggressive   daily hours television   total total
  behavior   less than 1   1 to 3   3 or more   at 16 at 22

+ +   4     10     18     32   32  
+ -   4     11     18     33   33  
  subtotal:     8     21     36     65   65

- +   1     77     49     127   166  
- -   79     288     148     515   476  
  subtotal:     80     365     197     642   642

  total:     88     386     233     707   707
  Table E: Reconstructed data describing the relation between low family income (poverty), daily hours of television at age fourteen and aggressive behavior at age sixteen — showing no rise in aggressive behavior for low income adolescents
  Again it is highly improbable that the original data of the Children in the Community Study looked like this, as these figures show a relatively high correlation between "low family income" and "aggressive behavior". In the case over all the categories of "daily television time" half of the youths from low income families would have shown some aggressive behavior at age sixteen against 20% of the youths from higher income failies. Moreover, the rise in "aggressive behavior" is located only in the group of adolescents from relatively high income groups. Here "low family income" and "daily televison time" together explain 5.9% of variance in "aggressive behavior". By itself "low family income" and "daily televison time" respectively explain 3.5% and 1.8% of variance in "aggressive behavior". The remaining 0.6% of explained variance can be attributed to the interaction of "low family income" and "daily televison time".
   
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