adding keywords or changing advert.....

Does addiing keywords or changing the description have an adverse effect on a campaign?

i.e Does it reset the cpc or ctr??

 

As much I know statistic within campaign remain after changing or adding.

 

Historical keyword data is not reset when adding a new keyword or changing a url. Your ad will need to be reapproved so their will be a delay in getting back to full network exposure.