It is highly unlikely that the results of a one-time, standardized test offer a valid representation of a puppy's overall behavior and temperament. A single test indicates how the pup faired on a certain day, with a particular tester, under strictly monitored conditions
...In reality, many so-called aptitude/temperament tests are in fact, simple behavior tests. Simple one-time observations of a puppy's behavior are used to make sweeping generalizations about the pup's future temperament. Results of a simple visitation test have been grossly extrapolated to draw quite complicated conclusions about trainability and temperament. If the intention is to evaluate these various attributes, we would do much better to specifically appraise the pup's learning speed, attention span, recognition, recall and memory, or to investigate reactiveness, bounce-back (forgiveness), specific sensitivities and fears.
...Predictive Value of Tests
Although it is widely assumed that it is possible to accurately predict a dog's adult temperament from early testing, this has never actually been satisfactorily demonstrated in any scientific study. An interested breeder or trainer can endeavor to answer this question
...
With a large amount of variation between the test results in any series, the predictive value is minimal. If anything, it predicts a lack of prediction — producing no reliable assessment of how the dog acted in the past, it offers little help in forecasting the dog's actions in the future.
The older the dog at the time of each test, the greater is the predictive value of the results. Young animals have a high degree of plasticity in terms of their temperament and behavior repertoire, which are continually modified with each new experience. This is reflected by gross changes in each pup's absolute performance (average contact latencies) and by changes in the pus' relative performance (vis a vis other littermates) prior to six months of age. With older dogs, the rank order of approach times remains more a less the same. Adolescent and adult dogs are much more resistant to change, even with human intervention. A six-month old dog would require hundreds of trials to significantly improve its contact latency with strangers.
Early testing only predicts how the puppies might develop if left to their own devices and if all treated equally. But pups and adolescents are never treated equally. Some grow up in great homes, others in good homes and yet others in bad homes — some poor dogs grow up with owners who should not be allowed to keep a rock, let alone a dog. The owner-variable far overshadows potential puppy predispositions. And without a doubt, a poor puppy prospect in a good home almost always becomes a better canine companion than a good puppy prospect in a poor home.
Human intervention is certainly the most important factor determining predictability: whether or not the new owners capitalized on the dog's potential good characteristics and/or resolved expected or incipient bad characteristics that were revealed in earlier testing. It would be naive to expect a dog to cure his own faults. Behavior and temperament are in a state of constant flux, and without human guidance, faults generally tend to get worse rather than better. It would be tantamount to stupidity to test a pup and discover that he is fearful, rambunctious, or aggressive, yet leave him to develop in this expected fashion. Surely a major reason for early testing is to locate potential or incipient problems and solve them before they become full-blown. Similarly, it would be utter folly to assume that a dog's naturally good temperament will necessarily remain that way indefinitely. As soon as owners become presumptively audacious about their pet paragon with the perfect personality, the dog's demeanor will predictably begin to deteriorate.