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EMPLOYMENT  PSYCHOLOGY

results  computed  in  the  manner  previously  described.
Below  is  a  table  showing  the  correlation  between  the  final
rankings  of  each  foreman  and  the  ranking  based  on  three
tests  taken  together:

Correlations

ist  Group  (12)  90
2nd  Group  (11)  65
3rd  Group  (12)  50

The  correlations  in  groups  two  and  three  are  not  as  high
as  those  in  the  first.  However,  group  two  had  met  only
sixteen  times  which,  at  two  and  one-half  hours  a  session,
meant  only  four  days  of  actual  work.  The  third  group
had  met  only  twelve  times,  which  meant  only  three  days
of  actual  work.  Consequently,  although  the  correlations
between  the  opinion  of  the  instructors  and  the  rank  of
the  pupils  in  the  tests  are  already  significant,  their  true
significance  cannot  be  stated  until  more  time  has  elapsed.
It  may  or  may  not  be  significant  that  the  trend  of  the
correlations  varies  directly  with  the  length  of  time  which
has  expired.
In  order  to  obtain  a  true  estimate  of  the  ability  of  a
group  of  apprentices  and  trained  workers,  it  is  necessary
to  give  to  the  entire  group  a  thoroughgoing  practical
examination  in  the  work  which  they  are  supposed  to  have
learned.  Very  few  apprentice  schools  make  a  practice  of
this  precaution.  They  assume  that  when  a  boy  has  passed
through  their  various  grades  and  classes  of  work,  he  is
qualified  to  serve  as  a  full-fledged  journeyman.  This
assumption  is  patently  unjustified.  Moreover,  it  increases ­
  the  difficulty  of  obtaining  reliable  information
about  the  relative  abilities  of  a  class  of  apprentices  and