1. Online comparison sites - There are many sites online with the sole purpose of comparing nanny agencies according to price, reputation, geographic location and expertise. For some of these web sites, a registration is required; however, for most, you simply have to visit them and compare the agencies that you want. The best comparison sites will have contact information and direct links for getting in touch with the agency that you choose.
2. Individual reviews - The many strictly review sites online also include entries from people that have used nanny services. You may find this method the most telling of all of the online methods of comparing nanny agencies, as people tend to be quite forthcoming on these individual review sites. You can also verify the identity of many people on these sites much more readily than you can with comparison sites, as some agencies will pay others to post positive reviews on those sites.
3. Friends - The most traditional way of comparing nanny agencies is simply to ask friends and family members whom you trust about who they have used for their services. You can definitely be most assured that these people will have your best interests at heart, and you can also go about this type of review knowing that the people who are telling you their information also know you. This can be a double edged sword, however.
4. Tryouts - Some people consider the best way to try out different nanny agencies is simply to give them all a tryout session one after the other. The upside to this method is that you get to see each and every nanny service up close and personal. The downside is that people tend to know about the time limits on these types of tryouts and will put their best foot forward for it. However, they may not be able to keep up that service level over a sustained period of time.
5. Professional rating agencies - The home care industry has many regulatory bodies which rate those agencies within the industry. Although these are the coldest and most scientific ways of ranking agencies by far, they may not be able to fully capture the essence of what really makes a nanny connect with a client.
6. Call ins - Some people choose to call in and base their rating of an agency on the professionalism of the experience on the call. A company that is professional on the phone will most likely be professional in other aspects of their business as well.
7. Directories - Professional nanny agencies will be listed in professional directories compiled for the purpose of listing all valid agencies. This is definitely a way to determine who has a more professional business structure.
8. Memberships – Reputable agencies will hold membership in professional organizations like the International Nanny Association and the Association of Premier Nanny Agencies. These organizations sets professionals standards for their members.
9. Observation - Some agencies allow prospective clients to view their nannies with other clients on the job.
10. Asking a professional - Asking a retired professional for their opinion is often one of the best ways to get the best nanny for the job.

Although there are many different ways to compare nanny agencies, perhaps the best method for comparing them is to take two or more of the above techniques in tandem. Each technique tends to compare a particular characteristic, and so to get a fully rendered picture, more than one test may be appropriate.