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<Paper uid="J97-4002">
  <Title>An Empirical Approach to VP Ellipsis</Title>
  <Section position="4" start_page="0" end_page="527" type="intro">
    <SectionTitle>
(VP (-NONE- ,?,))
</SectionTitle>
    <Paragraph position="0"> In the Brown Corpus, VPE occurrences are not labeled in this way. We searched for occurrences of a sentence (S) with an auxiliary (AUX) but no VP.</Paragraph>
    <Paragraph position="1"> To evaluate our identification criteria, we performed a manual search for VPE occurrences in a sample of files constituting about 3.2% of the Treebank. 2 In this sample, we found that the Recall was 44%, and the Precision was 53%, as depicted in Table 1.</Paragraph>
    <Paragraph position="2"> In this sample, there were 27 valid VPE occurrences that were missed. We tested VPE-RES on these examples, and found that its performance was comparable to its performance on the examples that were automatically identified. The results are given in Table 2, which also includes results on the complete corpus, for ease of comparison. 3</Paragraph>
    <Section position="1" start_page="526" end_page="527" type="sub_section">
      <SectionTitle>
2.2 Coding the Data
</SectionTitle>
      <Paragraph position="0"> All the examples of VPE were coded for the correct antecedent by two human coders.</Paragraph>
      <Paragraph position="1"> We performed some comparisons of coder responses with one another, based on our three success criteria. On a sample of 162 examples, the results were as shown in Table 3.</Paragraph>
      <Paragraph position="2"> In this sample, there was only one example in which coder agreement failed according to the Head Overlap criterion:  Computational Linguistics Volume 23, Number 4 Here are the two choices: Coder 1: prevails in the financial markets Coder 2: acts as a haven The following is an example where the coders disagreed according to Head Match, although they agreed according to Head Overlap: (2) By contrast, in 19th-century Russia, an authoritarian government owned the bank and had the power to revoke payment whenever it chose, much as it would in today's Soviet Union.</Paragraph>
      <Paragraph position="3"> Coder 1: revoke payment whenever it chose Coder 2: owned the bank and had the power to revoke payment whenever it chose In the following example, the coders disagreed according to Exact Match, although they agreed according to the other two success criteria: (3) When bank financing for the buy-out collapsed last week, so did UAUs stock.</Paragraph>
    </Section>
  </Section>
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