Which verb form follows after "Something we can do, is "

Which of the following is correct?

• Something we can do is investigate the effects of...
• Something we can do is investigating the effects of...

I would say it's the first, but based on intuition rather than on grammar - someone I'm writing a text with thinks it's the second.

Can someone explain more formally which form is correct?

Edit

Some more context:

As actual costs are unknown, we cannot test if our model is successful on this basis. Something we can do, however, is investigate the consistency of our model over time. Although the structure...

These are the opening sentences of a paragraph.

Solution 1:

"Investigate" would be right in this sentence. This may not be the conventional way of doing it, but what I usually do in this situation is, strip the first verb "do" and the unnecessary word, like "something" (I'm doing it in this sentence right here, stripping off the "what" and "do"). Your sentence then reads:

We can ---- the effects of..

and the right word there would be "investigate" and not "investigating"

My sentence "what I usually do in this situation is, strip the first part of the verb and the unnecessary word" when stripped, would read:

I usually ---- the first verb..

and the right word here would be "strip" and not "stripping"