First, this question needs to be carefully contextualized.
The idea of "validating stereotypes" is sure to rub a lot of people the wrong way, particularly those who feel that all stereotypes are wrong and therefore cannot be validated. In fact, we all stereotype on an everyday basis; we might assume that someone talking to themselves and walking haphazardly is drunk or mentally ill, and adjust our behavior based on that perception. This is stereotyping just as much as saying, for example, that immigrants are lazy. The difference is that one is based on an empirically observed behavior, whereas the other is (most likely) not; has one observed, with certainty, that the majority of immigrants are lazy? Doubtful. This stereotype is easily invalidated.
Thus, the question of "validating" a stereotype depends upon the manner and context in which the stereotype is articulated. We might state "all Americans speak English". This is a stereotype, and one which I can easily invalidate based on the fact that I have met American citizens who don't speak English. If I were to modify this stereotype slightly, into "MOST Americans speak English", the semantics have changed slightly, but are essentially the same, and can easily be validated. This is how we can (and must) articulate a stereotype in a way that can be validated.
What does validation require? Validation is defined as a measure of accuracy; to avoid bias or errors due to interpretation, we could look for accuracy based on how closely a statement matches empirical fact. "Most Americans speak English" can be validated based on demographic surveys and feedback that indicate a majority of Americans speak English, but this cannot be construed beyond the contextual statement. Even if 99% of Americans speak English, "all Americans speak English" is still invalid.
What is eligible for validation? A stereotype which makes a general, but not completely definitive, statement about East Asians will be the most useful to us. We should focus on ones that involve careers, education, and income, because these are figures which can be attached to empirical data. In contrast, stereotypes such as "Asians are bad drivers" is more difficult to validate because the definition of a "bad" driver is ambiguous, largely a matter of opinion, and cannot be measured solely through statistics such as records of traffic collisions or insurance rates.
Here are some stereotypes we can use;
- East Asians predominately work in high-profile, high-education careers, such as computer science, engineering, math and data analysis, doctors, professors, and research laboratories. This stereotype can be validated (or invalidated) by investigating the demographic data published by the Bureau of Labor Statistic (included in my sources)
- East Asians typically do better in school, score higher on tests, and have a higher proportion of academic degrees than other racial groups. This can be evaluated based on statistics published by the Department of Education, individual states and school districts, colleges, and testing companies.