When it comes to defining good type it seems that there really is no fixed consensus, and so type remains a somewhat vague idea. There are, however, generally accepted brief descriptions of what a buck and a doe should look like (taken form the NFRS standards of excellence):

"The rat shall be of good size, does long and racy, bucks being of a bigger build, arched over the loin, firm fleshed with clean, long head, but not too pointed at the nose. The eyes shall be round, bold, clean and of goods size. The ears shall be of good size, well formed and widely spaced. The tail shall be cylindrical and as long as the body, thick at the base, tapering to a fine point. The ears, feet and tail shall be covered with fine hair. The coat shall be smooth and glossy (except for the Rex type). Bucks are longer than does and have a harsher coat."

The difficulties come in interpreting what this description means. For instance the description calls for a clean, long head - but there is a desired 'excellent' head length, beyond which the rat will be described (by a judge) as having a long head. Similarly, the ears are to be wide set, but breeding for width between the ears can lead to a look where the rat has ears that are set slightly onto the side of the rats head (as though he's been wearing a hat that has pushed his ears to the side). Judges may make comment about 'dumbo carriers', but this has nothing to do with the dumbo gene. What is the 'perfect' head length, ear spacing, ear shape/size, eye size or indeed, body shape, is to some degree within the eye of the individual judge. This accounts for why an adult rat whose shape is no longer changing can be judged by one person to have a long head, and by another a week later to have a nice head. One way to get a good feel for the quality and type of a rat (if you cannot see this for yourself) is to have it commented on by as many trained judges as possible. There will be differences in the detail of what is said, but you should be able to get an overall impression of whether it is considered to be a nice typey rat.

If you are considering breeding it is wise to try to learn for yourself what is considered to be 'good type'. Make a point of looking at winning rats at shows (not always an indicator - as a rat can come first out of 1 and still not be of particularly good type). Ask the people who win BIS and RBIS if you can look at the rats before they get whisked away, and if you're lucky enough to spot an off-duty judge then ask them if they can pick out a few rats with good type for you. You can also approach the judge with your rat for comment, after they have finished judging. Tell the judge you are thinking of breeding from the rat and ask for their opinion - but bear in mind that they might advise you not to breed from it for some reason!

Selective breeding
Particularly up here in the north it is often difficult to get hold of really good foundation stock for starting (or improving) a line. It is important to realise that you don't need to start of with perfection. Careful selective breeding can improve almost any attribute. What is important is not to begin with two rats who are mediocre in everything. Then you will only ever produce mediocre ratlets! Look for two rats of good overall confirmation. Substantial rats with good bone structure; a large, muscular buck and a big racy doe. If one has a fault make sure that the same attribute in the other is good. For example, creased ears are considered to be a fault in the dumbo. If you mate a dumbo with creased ears to one with great ears you should have some babies in the litter with good ears-and the best of these you select for breeding. While not all genetic inheritance is either simple (recessive or dominant genes) or predictable, most faults can be improved by selective breeding. Whatever faults the rats in your line have breed away from them by looking for rats (from the line or outcrosses) that are great in those particular areas, as well as being nice substantial rats. Then select the best of the litter for the next generation.

Some breeders would strongly suggest that it is not possible to produce great quality rats without culling litters down and only allowing does to raise a limited number of young. Many breeders who do not agree with culling are working hard to prove this notion wrong. I have to confess that I am amongst those who feel that temperament and health are priorities in breeding quality pet rats, and believe that over a period of time it is also possible to improve type, colour and markings without culling.