ret·ro·spect 
/ˈrɛtrəˌspɛkt/ noun
/ˈrɛtrəˌspɛkt/ noun Meaning:
in retrospect
: when thinking about the past or something that happened in the past
▪ In retrospect, I made the right decision. ▪ What is interesting in retrospect is how wrong our assumptions were.
▪ In retrospect, I made the right decision. ▪ What is interesting in retrospect is how wrong our assumptions were.
