It's always good to STICK WITH THE EVIDENCE, and treat words like "giftedness" with some skepticism. It's not the words --- it's the FACTS that matter ! :)
The most common definition of giftedness is based on the full scale IQ, so the short answer would be "no you can't". However, there are huge variations across authors concerning the "right" definition of giftedness, and some authors (and many practitioners) use a less conservative definition in which someone is gifted as soon as one of the sub scale is high enough.
So the long answer is : yes you can if you chose to use a liberal definition of giftedness that has supporters, but this is not the most common definition.
Hi Muriel. People usually have the understanding of giftedness as prodigal giftedness, such as Nicolas seems to be pointing to. To consider 1 in every 20 children as gifted is not a liberal approach, is just what investigators and academics in the giftedness area consider a standard approach. Much can be said about giftedness and I don't intend to bring it here. I suggest you read materials from Francois Gagné. You should be careful with labels but invest on the child's interests exploration and development. According to the definitions the term giftedness provides a general reference to a wide spectrum of abilities without being specific or dependent on a single measure or index. It is generally recognized that approximately five percent of the student population is gifted. Take care.
Strengths from a neuropsychological perspective are seldom homogenous. I recently placed a 13 year old in community college as he was a phenome in architecture although his full scale IQ was not that spectacular.
It's always good to STICK WITH THE EVIDENCE, and treat words like "giftedness" with some skepticism. It's not the words --- it's the FACTS that matter ! :)
My opinion is that we must be careful when using a single score for diagnostic hypothesis. For reliability reasons, a score of 130 in Verbal Comprehension or Perceptual Reasoning does not offer sufficient guarantees to diagnose the giftedness. In the WISC-IV Technical and Interpretive Manual (UK Edition) the Standard Errors of Measurement of these Indexes are 3,78 and 4.15 respectively and the 95% confidence interval are 121-135 and 121-136 respectively (Table A.6; Administration and Scoring Manual). For validity reasons even higher scores, as 140 or more do not offer sufficient guarantees in diagnostic hypotheses of giftedness. I think the best thing to have a decent degree of accuracy is determine all the Composite scores of WISC-IV (VCI, PRI, WMI, PSI and FSIQ), check the profile obtained with that found in gifted and confirm the hypothesis of giftedness with some criterion validity (stick with the evidence, as Bernard said) and other tests such as the Advanced Progressive Matrices or other similar tests.
Research has shown that those perfectly integrated gifted young become nearly average performers (in the upper range) when adults. The point is, the psychometric approach is only one indicator. Many times it fails to identify high potential. What you might wanna do is try and favour the child's skills development, in his own areas of interest. All else is commentary.
It covaries with it extensively but it is not fully commensurate. Giftedness is related to other variables as well, such as motivation to pursue goals and fit them into the functioning of groups. These are not captured by intelligence tests.
I think this question is unclear from the start. When we talk about diagnose, aren't we addressing a problem? (i.e. a pathology) There are some common issues with gifted people (not just the young ones), but usually it has more to do with emotional hardship and social inclusion than with the giftedness it self.
It's easy to understand. A gifted child on an age based school level, might be bored most of the time and even get low grades on account of his lack of interest. Besides, (s)he can never be fully integrated with his pairs as they often have particular interests that don't appeal to the normative population. If the child attends to school on a performance based level, the issues are different but also relate to social integration and emotional management (frustration mainly).
What all educators should know is that these kids need to have opportunities to pursue their own interests, and be given support regarding their emotional lives and social inclusion (whether on an age level or performance level basis). That way they are allowed to become experts on something, but will keep a normative development on other aspects of their lives. That's how they can become productive and fulfilled adults.
Regarding testing, you should not fully rely on psychometric instruments as they can only capture a narrow range of skills. Imagine a great dancer or sports prodigy, do you think (s)he should score high on an intelligence test (e.g. WISC)? What if (s)he doesn't, no more educational opportunities to fallow their passion?
Again, intelligence tests are only an indicator. If you find out (by any means) that a child has a particular song interest or performance in any particular area of human activity, allow them the chance to fully bloom their potential. Keep an eye on their "human dimensions" so they may have a normal development on every other aspect of their lives. And drop the diagnostics mind frame that's holding you back from having an effective intervention.