DROP

DROP
Overview
Full name	Discrete Reasoning Over Paragraphs
Abbreviation	DROP
Description	A reading comprehension benchmark requiring discrete reasoning and mathematical operations over paragraphs
Release date	2019-03-01
Latest version	1.0
Benchmark updated	2019-04
Authors	Dheeru Dua, Yizhong Wang, Pradeep Dasigi, Gabriel Stanovsky, Sameer Singh, Matt Gardner
Organization	Allen Institute for AI, UC Irvine
Technical Details
Type	Reading Comprehension, Discrete Reasoning, Mathematical Reasoning
Modality	Text
Task format	Extractive/Abstractive Question Answering
Number of tasks	5 reasoning types
Total examples	approximately 96,000 questions
Evaluation metric	F1 Score, Exact Match
Domains	Sports, History, Wikipedia articles
Languages	English
Performance
Human performance	96.0% F1
Baseline	32.7% F1 (2019)
SOTA score	87.1% F1
SOTA model	Claude 3.5 Sonnet
SOTA date	2024
Saturated	No
Resources
Website	Official website
Paper	Paper
GitHub	Repository
Dataset	Download
License	CC BY-SA 4.0

DROP (Discrete Reasoning Over Paragraphs) is a reading comprehension benchmark that requires artificial intelligence systems to perform discrete reasoning operations over textual content. Released in March 2019 by researchers from the Allen Institute for AI and UC Irvine, DROP challenged the prevailing paradigm in reading comprehension by requiring systems to perform mathematical operations, counting, sorting, and comparison operations rather than simply extracting text spans. The benchmark contains approximately 96,000 questions created adversarially to expose weaknesses in contemporary reading comprehension systems.

Overview

DROP represents a significant advancement in evaluating genuine comprehension and reasoning capabilities in AI systems. Unlike traditional reading comprehension benchmarks that primarily test span extraction abilities, DROP requires models to understand paragraph content comprehensively and perform discrete operations including addition, subtraction, counting, sorting, and comparison. This design philosophy ensures that systems must develop true understanding rather than relying on superficial pattern matching.

Significance

The development of DROP addressed critical limitations in existing reading comprehension evaluation:

• **Beyond Span Extraction**: Requires mathematical and logical operations over text
• **Multi-step Reasoning**: Questions demand combining multiple pieces of information
• **Reference Resolution**: Systems must resolve pronouns and references across passages
• **Adversarial Robustness**: Questions specifically designed to defeat baseline systems
• **Practical Relevance**: Operations mirror real-world information processing tasks

Dataset Structure

Question Categories

DROP organizes questions into five primary reasoning categories:

Category	Percentage	Description	Example Operation
**Addition/Subtraction**	~25%	Mathematical operations on numbers in text	"How many more yards did X gain than Y?"
**Counting**	~20%	Counting entities or events	"How many touchdowns were scored in the game?"
**Selection**	~20%	Choosing specific items based on criteria	"Who scored the longest touchdown?"
**Minimum/Maximum**	~18%	Finding extreme values	"What was the shortest field goal?"
**Comparison**	~17%	Comparing quantities or attributes	"Which team had more first downs?"

Answer Types

DROP supports multiple answer formats to accommodate different reasoning operations:

Answer Type	Frequency	Description	Example
**Number**	~45%	Numeric values with optional units	"42 yards", "7 touchdowns"
**Text Span**	~40%	Extracted from passage or question	"New England Patriots"
**Date**	~15%	Temporal information	"September 15, 2018"

Data Distribution

The dataset is divided into standard splits:

Split	Number of Questions	Number of Passages	Purpose
**Training**	~77,400	~6,700	Model training
**Development**	~9,540	~950	Hyperparameter tuning
**Test**	~9,500+	~950	Final evaluation (hidden)
**Total**	96,567	~8,600	Complete dataset

Creation Methodology

Adversarial Collection Process

DROP employed a sophisticated adversarial collection methodology:

1. **Baseline System**: BiDAF model trained on SQuAD used as adversary 2. **Worker Instructions**: Crowdworkers instructed to create questions the baseline cannot answer 3. **Question Validation**: Multiple workers validate each question-answer pair 4. **Iterative Refinement**: Questions refined based on validation feedback 5. **Quality Control**: Automatic and manual checks ensure question quality

Source Material

The passages in DROP are drawn from:

Source	Percentage	Content Type	Characteristics
**Sports Game Summaries**	~60%	NFL game descriptions	Rich in numbers, statistics, events
**Wikipedia History**	~40%	Historical articles	Dates, quantities, comparisons

These sources were chosen for their natural abundance of quantitative information and discrete facts amenable to mathematical reasoning.

Evaluation Methodology

Metrics

DROP uses two primary evaluation metrics:

Metric	Description	Calculation	Use Case
**F1 Score**	Token-level overlap	Harmonic mean of precision and recall	Primary metric
**Exact Match (EM)**	Complete answer match	Binary exact match after normalization	Secondary metric

Answer Normalization

The evaluation script performs extensive normalization:

• Remove articles (a, an, the)
• Convert to lowercase
• Remove punctuation
• Normalize numbers (for example "one" → "1")
• Handle date formats consistently

Evaluation Challenges

Several technical challenges have been identified:

Challenge	Description	Impact	Mitigation
**Tokenization Issues**	Different tokenizers affect scoring	Score variations	Standardized preprocessing
**Number Formatting**	Various valid number representations	False negatives	Comprehensive normalization
**Multiple Valid Answers**	Some questions have multiple correct answers	Underestimated performance	Set-based evaluation

Performance Evolution

Current Leaderboard (2024)

Rank	Model	F1 Score	EM Score	Key Innovation
1	Claude 3.5 Sonnet	87.1	~85	Advanced reasoning
2	Gemini 1.5 Pro	78.9	~76	Long context understanding
3	GPT-4 Turbo	~77	~74	Improved mathematical reasoning
4	GPT-4o	~75	~72	Optimized architecture
-	Human Performance	96.0	94.1	Expert baseline

Historical Progression

The dramatic improvement in DROP performance over time:

Year	Best Model	F1 Score	Improvement	Key Development
2019	BiDAF (baseline)	32.7	-	Initial baseline
2019	NAQANet	47.0	+14.3	Numerical reasoning modules
2020	QDGAT	70.6	+23.6	Graph attention networks
2021	T5-large	79.1	+8.5	Pretrained transformers
2023	GPT-4	~82	+3	Large language models
2024	Claude 3.5 Sonnet	87.1	+5.1	Enhanced reasoning

Key Techniques and Innovations

Successful Approaches

Research on DROP has led to several important technical innovations:

Technique	Impact	Description	Representative Models
**Numerical Reasoning Modules**	High	Specialized components for mathematical operations	NAQANet, NumNet
**Graph Neural Networks**	Medium	Representing passage structure as graphs	QDGAT
**Program Synthesis**	High	Generating executable programs for reasoning	NeRd, OPERA
**Chain-of-Thought**	High	Step-by-step reasoning generation	GPT-4, Claude
**Tool Use**	Medium	Calculator and symbolic math integration	Various LLMs

Architecture Evolution

The progression of architectures successful on DROP:

1. **Early Neural Models** (2019): BiDAF with numerical heads 2. **Graph-Based Models** (2020): QDGAT, HGN 3. **Pretrained Transformers** (2021): T5, BART with task-specific fine-tuning 4. **Large Language Models** (2023+): GPT-4, Claude with few-shot prompting

Challenges and Limitations

Dataset Limitations

Limitation	Description	Impact
**Domain Specificity**	Heavy focus on sports and history	Limited generalization
**Annotation Artifacts**	Patterns in crowdsourced questions	Potential shortcuts
**Evaluation Issues**	Normalization and tokenization problems	Scoring inconsistencies
**Static Nature**	Fixed question set	Risk of overfitting

Known Technical Issues

Several technical issues have been documented:

• **Answer Normalization**: The Hugging Face team identified problems with the original normalization
• **Preprocessing Errors**: EleutherAI found systematic errors in official preprocessing
• **Token Handling**: Models sometimes receive 0 F1 due to formatting issues

Research Impact

Influence on Field

DROP has significantly influenced reading comprehension research:

Area	Impact	Development
**Numerical Reasoning**	Spurred research in mathematical NLP	NumNet, MathQA
**Multi-hop Reasoning**	Advanced multi-step reasoning research	HotpotQA follow-up
**Program Synthesis**	Integration of symbolic reasoning	Neural program synthesis
**Evaluation Methods**	More comprehensive evaluation metrics	Beyond span extraction

Related Benchmarks

Benchmark	Year	Focus	Relation to DROP
SQuAD	2016	Span extraction	Predecessor, simpler
DROP	2019	Discrete reasoning	Current benchmark
IIRC	2020	Multi-hop reasoning	Complementary focus
NumGLUE	2022	Numerical reasoning	Specialized follow-up

Applications and Use Cases

Practical Applications

Technologies developed for DROP have found applications in:

• **Financial Analysis**: Extracting and computing financial metrics from reports
• **Sports Analytics**: Automated game summary analysis
• **Historical Research**: Quantitative analysis of historical texts
• **Educational Systems**: Automated problem solving and tutoring

Future Directions

Ongoing Research

Current research directions inspired by DROP include:

1. **Compositional Reasoning**: Breaking complex operations into primitive steps 2. **Symbolic Integration**: Combining neural and symbolic approaches 3. **Explainable Reasoning**: Generating interpretable reasoning chains 4. **Robust Evaluation**: Addressing normalization and scoring issues 5. **Domain Extension**: Expanding beyond sports and history

Significance

DROP has fundamentally advanced the field of reading comprehension by demonstrating that true understanding requires more than pattern matching and span extraction. The benchmark's requirement for discrete mathematical and logical operations over text pushed the development of models with genuine reasoning capabilities. The improvement from 32.7% to 87.1% F1 score represents not just numerical progress but qualitative advances in how AI systems process and reason about textual information.

While current models have made significant progress, the gap to human performance (96% F1) indicates remaining challenges in achieving robust, generalizable reasoning over text. DROP continues to serve as a valuable benchmark for developing and evaluating reading comprehension systems that can perform practical, real-world information processing tasks.

See Also

• Reading Comprehension Benchmarks
• SQuAD
• Mathematical Reasoning in NLP
• Allen Institute for AI
• Discrete Reasoning