VADER Sentiment Analysis

Overview

VADER (Valence Aware Dictionary and sEntiment Reasoner) is a lexicon and rule-based sentiment tool optimized for social media. Returns compound score [-1, +1] combining positive, negative, and neutral proportions. Runs in O(n) per text where n = word count. No training required.

When to Use

Trigger conditions:

• Analyzing sentiment in social media posts, tweets, or reviews
• Quick sentiment scoring without ML model training
• Processing text with slang, emoticons, and informal language

When NOT to use:

• For formal/academic text (VADER is tuned for social media)
• When domain-specific sentiment matters (e.g., financial sentiment — use FinBERT)
• When sarcasm detection is critical (VADER doesn't detect sarcasm)

Algorithm