Can "poor" subdomains drop PR of the root domain?

[ckilgore]

The page rank of my company's website has dropped from a 6 to a 4 over the past year or so. In that time, we implemented subdomains for development sites to show clients progress on their websites. I noticed that our "dev" sites are being indexed while in development and my question is, will Google drop pagerank of our root domain purely off of these "dev" subdomains?

Example - our site is www.oursite.com

Dev site - development1.oursite.com

I just began investigating the drop and this came to my mind yesterday but am not too sure what type of impact these non-credible subdomains will have on our root domain. Any thoughts?

[RyanKent]

Your subdomain is seen as a completely different site. Google does not assume your subdomain is related to your main site.

For example, if you visit wordpress.com you will see someone probably has the URL seo.wordpress.com. Whatever happens on that subdomain should not have any impact on any other subdomain or primary domain for wordpress.com.

[ckilgore]

Thank you, didn't even think of it in that sense (kind of have blinders on in this case and am looking for an easy answer, which probably doesn't exist). Appreciate the feedback!

[RyanKent]

Another thought....

robots.txt shouldn't be used much but dev sites are a perfect example of where it should be used. Block crawlers from those dev sites.

[ckilgore]

I agree.

I have seen posts on SEOmoz and elsewhere throughout the SEO community that others are noticing drops in PR with no impact on traffic. I am not seeing a noticeable drop in traffic so the PR isn't concerning me too much but I am curious.

Have you noticed anything like this post Panda and do you think the panda update has any impact on the PR directly (I see how it would with poor content --> harder link building)? Again, I appreciate the feedback!