A the high levels of investment in IT incremented the production capacity in the US in the 70s and 80s.
B history shows that technological innovations need some time to be mastered before they actually become efficient tools.
C cultural changes have been one of the main causes of the IT unstable outputs.
D steam engine and electricity are examples of technology innovations promptly put to efficient use.
E new technologies to measure the productivity growth associated to IT will be studied in the next decades.