2. Prior CHC COG-ACH research syntheses summaries
The first attempt to summarize the cognitive-achievement relations research vis-à- vis a CHC lens (CHC COG-ACH) was presented in McGrew and Flanagan's (1998)  Intelligence Test Desk Reference: Gf- Gc Cross-Battery Assessment (ITDR)
This summary was subsequently extended in the CHC cross-battery (CB) book series, with the most recent CHC COG-ACH relations summary tables presented in the Achievement Test Desk Reference(ATDR; Flanagan, Ortiz, Alfonso, Mascolo, 2006). As far as we know, no other CHC- specific COG- ACH research syntheses have been published.
As far as we know, the only attempt to summarize the extant CHC COG-ACH research is a set of regularly updated summary tables published in the CHC cross- battery assessment series of books.  We classify the latest iteration (Flanagan, Ortiz, Alfonso & Mascolo, 2006)  as a narrative research synthesis as no attempt was made to systematically quantify the significance of results across studies, an approach typically defined as  meta-analysis (Cooper, 1998).
Flanagan et al. (2006) identified potential CHC COG-ACH research studies through two primary steps. First, research studies and reviews reporting statistically significant relations between cognitive abilities and school achievement were identified via a search of the PsycINFOelectronic database. Next, an ancestral search strategy of the references identified in step one revealed other articles for review. Flanagan et al. (2006) classified the research reports into three categories: (a) key CHCstudies—CHC-organized studies that included markers for most broad CHC cognitive abilities; (b) reviews—non-CHC organized narrative or meta- analytic research syntheses reporting significant relations between cognitive abilities and school achievement; and (c) individual studies—single non- CHC empirical studies that investigated the relations between cognitive abilities and school achievement. For most of the research reports Flanagan et al. (2006) had to translate non-CHC defined cognitive abilities as per the nomenclature of the CHC taxonomy (e.g., phonemic awareness = narrow ability of phonetic coding under the broad domain of Ga). Flanagan et al.’s (2006) summary tables included 138 references for reading (8 key CHC studies; 23 reviews; 107 individual studies) and 37 references for math (3 key CHC studies; 5 reviews; 29 individual studies).