I know this question is similar to the one posted about hand washing with either cold or warm water, but I hope it can stand on its own. If not, I'll delete.
Alcohol and water are the most common ingredients in commercially available hand sanitizers.
These products are marketed under a variety of names and by differing companies, but they are all relatively similar, even though some use ingredients like Benzalkonium Chloride instead of ethyl alcohol. For the purpose of this question, they should all be treated equally, unless a particular formula or brand can be demonstrated to clearly stand out from the rest.
However, regardless of chemical makeup, it's common to encounter statements such as
Kills 99.99% of most common germs that may cause illness in as little as 15 seconds source
While I have had some difficulty finding anyone claiming these products to be more effective than hand washing, I have found statements such as the following...
alcohol-based hand sanitizer with emollients is actually better tolerated than soap-and-water hand washing - not drying and irritating. source
Soap and water
Not to go into detail about the documented difficulties Semmelweis had in introducing this concept to other doctors as a way to slow the spread of infection, handwashing has been fairly well accepted by the scientific community and the public in general.
Also, for the purpose of this question, I'm only referring to handwashing with regular soaps, and not specially made antimicrobial soaps.
Which method is more effective at removing germs from the hands, or are they equally effective?