longitudinal data vs time series

CFA Level I Quant
#1

Whats the difference between these two types of data?

Both seem same to me!

#2

Longitudinal data are multiple sets of time-series data for the same time period and the same company.

Quarterly P/E ratios from 2002 to 2012 for McDonald’s are time series data, as are quarterly dividend yields, quarterly earnings, and quarterly current ratios from 2002 to 2012 for McDonald’s. Tie all four up with a ribbon and bow, and you have longitudinal data for McDonald’s.

#3

thanks

#4

You’re welcome.