Exploratory Experimental Studies Comparing
Online and Off line Programming Performance
Two exploratory experiments were conducted at
System Development Corporation to compare debugging 
performance of programmers working under conditions
of on-line and off line access to a computer.  These 
are the first known studies that measure programmers'
performance under controlled conditions for standard 
tasks.  Statistically significant results of both experiments
indicated faster debugging under online 
conditions, but perhaps the most important practical finding
involves the striking individual differences 
in programmer performance.  Methodological problems encountered
in designing and conducting these experiments 
are described; limitations of the findings are pointed
out; hypotheses are presented to account for results; 
and suggestions are made for further research.
CACM January, 1968
Sackman, H.
Erikson, W. J.
Grant, E. E.
