In this sentence – However, firm's human resources, in and of themselves, did explain improved performance, and some firms gained IT-related advantages by merging IT with complementary resources – what does "in and of themselves" mean?
This is a great question, Steven.
Small words pose the biggest challenge to Chinese learners of English, don't you think?
I've often said that anyone who thinks his/her English is good/bad can test themselves by looking up the first entry in a dictionary – the letter "a", that is – and check to see if they have mastered its many various idiomatic usages, such as in your writing, there should've been an "a" or "the" preceding "firm's human resources". Won't do without one – "a" if you're talking about firms in general, "the" if you're addressing a particular one.
Other usages of "a" include: twice a day; take a good look at this; a crushing defeat; a few weeks from now; a knife and fork; a particularly fine Columbian coffee; a certain Mr Quinton; many a sleepless night...
Sure, you should pay attention to long and winding words like hippopotamus, but you should mind shorter words more – I mean all the a's, the's, if's, but's and only's. Trust in four-letter words (no pun intended) and shorter. That way, in short, you'll go far.
"In and of itself", by the way, means just itself, when considered alone and not in connection with other factors. For example, it's commonly believed that money makes people happy, but money does not have the power in and of itself to make people happy (or unhappy). It takes happy (or unhappy) people to make it happen. In other words, if considered alone, money remains innocent.
Anyways as an adverb, "in and of itself/themselves" is similar to itself/themselves (for emphasis), or intrinsically (talking about things' inherent nature and qualities), or per se (Latin for in itself, by itself).
And here are two examples of "in and of itself/themselves" to help deepen the impression.
1. Vision loss linked to greater risk of early death (Reuters, September 9, 2007):
Older men and women with cataracts or age-related macular degeneration (ARMD) are at increased risk for suffering an early death, relative to older people without these two types of visual impairment, a study hints.
But it's not clear, the study team notes, whether the vision loss is simply a marker for deterioration due to aging or if, in and of itself, the conditions boost mortality risk.
2. New York Times Puts Reader Comments on Main Page - Good Idea? (www.readwriteweb.com, October 12, 2007):
Silicon Alley Insider spotted the New York Times web site displaying reader comments prominently under the top story on their front page today. The comments in-and-of themselves are not newsworthy – they came from a post on the site's news blog and the Times has linked to comment threads on the main page before. But this is, to anyone's recollection, the first time the site has actually displayed the actual comments themselves on the site.