How Do You Decide If a PPC Campaign Is Worth Continuing?

Watch the trend, not just one bad day. If CTR and conversions improve with more data, continue. If CPA stays bad after proper testing, pause the campaign.

i'd also check whether the loss is concentrated before killing the whole campaign. if most of the spend is coming from a handful of sources/placements that produce nothing downstream, the campaign itself may still be viable. cut the obvious waste first and see what the remaining traffic does. i'd rather make that decision than kill an offer because the first traffic mix was bad.