Sentiment Analysis Annotation

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For a media analytics client, we annotated thousands of text samples across social media, product reviews, and support tickets to detect sentiment polarity and emotional tone. The project enabled scalable, high-quality sentiment classification for downstream applications in brand monitoring and market analysis.

Industry Marketing & Consumer Insights
Data 12,000 text samples, 3 sentiment classes (positive, negative, neutral)
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Industry Marketing & Consumer Insights
Data 12,000 text samples, 3 sentiment classes (positive, negative, neutral)

Task:

The client needed annotated data for training a sentiment analysis model. The task was to classify each text snippet by its emotional tone — positive, negative, or neutral — while considering the nuances of informal language, sarcasm, and context.

Key challenges included:

    • Subtle sentiment cues: Sentiment was often implied rather than explicit, especially in short-form content like tweets or support chats.
    • Ambiguity and subjectivity: Many texts were borderline in sentiment, requiring annotators to apply consistent interpretation rules.
    • Domain variation: The dataset spanned multiple domains (e.g., e-commerce, tech support, entertainment), each with its own tone, jargon, and sentiment indicators.

Solution:

  • 01

    Preparation and guidelines

    • Created domain-specific sentiment annotation guidelines with real-world examples
    • Defined detailed rules for handling sarcasm, negation, and mixed signals
    • Provided initial batches with expert-reviewed annotations as reference sets
    • Conducted remote training sessions with interactive exercises and QA discussion
  • 02

    Annotation process

    • Annotators labeled text samples using a structured 3-class system (positive, negative, neutral)
    • Borderline or uncertain cases were flagged for team review
    • Domain shifts were handled by tagging each sample with context metadata for future fine-tuning
  • 03

    Quality control

    • Weekly quality audits were performed on random samples by expert validators
    • Implemented a double-review process for low-agreement cases
    • Annotators received regular feedback based on error patterns and validation reports

Results:

  • Accurately annotated 12,000 text samples with sentiment polarity

  • Achieved inter-annotator agreement of over 92% on final batches

  • Developed scalable sentiment labeling workflows adaptable to new domains

  • Enabled the client to improve their model’s performance on noisy, real-world text data

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