Stephen Ndwiga

Key Skills

Software

Labelbox

Doccano

Top Subject Matter

AI Training Data

AI Training / Content Moderation

Conversational AI / NLP

Top Data Types

Text

Image

Document

Top Task Types

Classification

Entity Ner Classification

Freelancer Overview

Data Annotation Specialist (Freelance). Brings 4+ years of professional experience across complex professional workflows, research, and quality-focused execution. Core strengths include Labelbox and Doccano. Education includes Bachelor of Arts, University of Nairobi (2024). AI-training focus includes data types such as Text and labeling workflows including Classification and Entity (NER) Classification.

Labeling Experience

Data Annotation Specialist (Freelance)

LabelboxTextClassification

As a Data Annotation Specialist, I annotated and labeled large datasets for AI and machine learning models to ensure data quality. My work involved text classification, sentiment analysis, and named entity recognition tasks on varied textual data. I was responsible for reviewing and validating labeled data while ensuring confidentiality and adherence to strict guidelines. • Consistently maintained accuracy rates above 95% • Ensured timely delivery of annotated batches under tight deadlines • Handled sensitive or proprietary datasets with utmost confidentiality • Contributed to the quality assurance by validating peer annotations

As a Data Annotation Specialist, I annotated and labeled large datasets for AI and machine learning models to ensure data quality. My work involved text classification, sentiment analysis, and named entity recognition tasks on varied textual data. I was responsible for reviewing and validating labeled data while ensuring confidentiality and adherence to strict guidelines. • Consistently maintained accuracy rates above 95% • Ensured timely delivery of annotated batches under tight deadlines • Handled sensitive or proprietary datasets with utmost confidentiality • Contributed to the quality assurance by validating peer annotations

2024 - Present

image annotating and video datasets

ImageSegmentation

annotated image and video datasets using CVAT by labeling objects with bounding boxes and segmentation tools. ensured accurate and consistent data labeling to support computer vision and machine learning model training

annotated image and video datasets using CVAT by labeling objects with bounding boxes and segmentation tools. ensured accurate and consistent data labeling to support computer vision and machine learning model training

2024 - 2026

Content Reviewer / Data Labeling Assistant

LabelboxTextClassification

As a Content Reviewer / Data Labeling Assistant, I tagged and categorized textual and visual data to support AI model training. My work included identifying and correcting inconsistencies in labeled datasets and performing quality assurance. I also collaborated with team members to improve annotation guidelines and workflow efficiency. • Conducted quality checks to uphold required standards • Enhanced team performance through process optimization • Assisted in refining annotation instructions • Ensured datasets were accurate and consistent for downstream AI use

As a Content Reviewer / Data Labeling Assistant, I tagged and categorized textual and visual data to support AI model training. My work included identifying and correcting inconsistencies in labeled datasets and performing quality assurance. I also collaborated with team members to improve annotation guidelines and workflow efficiency. • Conducted quality checks to uphold required standards • Enhanced team performance through process optimization • Assisted in refining annotation instructions • Ensured datasets were accurate and consistent for downstream AI use

2023 - 2024

Sentiment Data Annotator (Project-based)

LabelboxTextClassification

I labeled sentiment datasets used in customer feedback and opinion analysis. This involved classifying text snippets by sentiment polarity and ensuring accurate annotation for high-quality training data. My work supported the development of sentiment analysis models in AI applications. • Focused on customer feedback classification • Maintained annotation consistency across datasets • Provided quality control through double-checking entries • Used annotation tools for efficient workflow

I labeled sentiment datasets used in customer feedback and opinion analysis. This involved classifying text snippets by sentiment polarity and ensuring accurate annotation for high-quality training data. My work supported the development of sentiment analysis models in AI applications. • Focused on customer feedback classification • Maintained annotation consistency across datasets • Provided quality control through double-checking entries • Used annotation tools for efficient workflow

2023 - 2023

NER Annotator (Project-based)

DoccanoTextEntity Ner Classification

I completed named entity recognition (NER) tasks for various structured language datasets. My work involved extracting and annotating entities such as person names, locations, and organizations in textual data. I contributed to improved NLP model accuracy through precise annotation and compliance with task specifications. • Improved data structure for downstream NLP use • Applied strict quality assurance protocols • Managed confidential and sensitive information • Utilized annotation tools to streamline NER processes

I completed named entity recognition (NER) tasks for various structured language datasets. My work involved extracting and annotating entities such as person names, locations, and organizations in textual data. I contributed to improved NLP model accuracy through precise annotation and compliance with task specifications. • Improved data structure for downstream NLP use • Applied strict quality assurance protocols • Managed confidential and sensitive information • Utilized annotation tools to streamline NER processes

2023 - 2023

Education

Work History