The purpose of this study is to determine two types of error gravity in a corpus of texts written by native Chinese learners of English (ELLs)—one that enriches the traditional construct of gravity found in error gravity research by including error frequency, or how often an error occurs in a text relative to others, as an intervening variable, and one that applies the new error gravity data in a practical way to help establish salient grammatical focal points for written corrective feedback (WCF). Previous error gravity research has suggested that the amount of irritation caused by error is determined by the extent to which an utterance departs from "native-like" speech. However, because these studies often neglect the role of frequency in determining gravity—relying on isolated sentences, pre-determined errors, and manipulated texts to define it—a more complete view of error gravity is needed. Forty-eight native English speakers without ESL teaching experience and 10 experienced ESL teachers evaluated a set of 18 timed, 30-minute essays written by high intermediate to advanced native-Chinese ELLs. Errors were identified, verified, tagged, and classified by the level of irritation they produced. Results show the most serious errors included count/non-count (C/NC), insert verb (INSERT V), omit verb (OMIT V), and subject-verb agreement (SV). The most frequent error type was word choice (WC), followed by singular/plural (S/PL), awkward (AWK), and word form (WF). When combined, singular/plural (S/PL), word form (WF), word choice (WC), and awkward (AWK) errors were found to be the most critical. These findings support Burt and Kiparsky's (1972) global/local error distinction in which global errors, or those lexical, grammatical and syntactic errors that affect the overall organization or meaning of the sentence (Burt, 1975) are deemed more grievous than local ones, which affect only "single elements (constituents)" (Burt, 1975, p. 57). Implications are discussed in terms of future research and possible uses in the Dynamic Written Corrective Feedback classroom.