Josphat (Githuka) G.-Data Annotation Lead
Check rate
Experience
Data Annotation Lead
Sigma AI
- Lead a team of 15 annotators on large-scale computer vision projects for autonomous vehicle systems
- Developed comprehensive annotation guidelines that improved inter-annotator agreement by 35 percent
- Implemented quality control processes that reduced error rates by 42% across all projects
- Collaborated with ML engineers to identify edge cases and improve dataset quality
- Managed annotation projects for Fortune 500 clients, delivering 100% on time
Data Annotation Specialist
DataWorks Inc
- Performed high-volume image segmentation and bounding box annotation for ecommerce AI systems
- Annotated text data for NLP projects including sentiment analysis and named entity recognition
- Trained new team members on annotation tools and quality standards
- Participated in guideline development and process improvement initiatives
- Maintained consistent annotation accuracy of 98.5 percent across all projects
Junior Data Annotator
Lionbridge
- Conducted image classification and tagging for facial recognition datasets
- Performed data validation and quality checks on annotated datasets
- Assisted in audio transcription and labeling for speech recognition projects
- Met daily annotation targets while maintaining high quality standards
Industry experience
See where this freelancer has spent most of their professional time.
Experienced in Information Technology, Automotive, and Professional Services.
Business area experience
See which departments and functions this freelancer has contributed to most.
Experienced in Quality Assurance, Project Management, and Information Technology.
Summary
Data Annotation Specialist with a decade of experience in preparing, labeling, and quality-checking diverse datasets for machine learning applications. Expertise in image, text, audio, and video annotation with proven ability to develop annotation guidelines, train teams, and implement efficient workflows. Strong background in computer vision and natural language processing projects with meticulous attention to detail and deep understanding of AI/ML data requirements.
Skills
- Image, Text, Audio & Video Annotation
- Data Labeling Quality Assurance
- Annotation Guideline Development
- Team Training & Supervision
- Project Management & Workflow Optimization
- Data Analysis & Validation
- Tool: Labelbox, Cvat, Prodigy, Vgg Image Annotator, Amazon Sagemaker Ground Truth
- Technical Skills: Python, Sql, Basic Data Analysis, Microsoft Office Suite
Languages
Education
Karlsruhe University
Bachelor of Science, Computer Science · Computer Science · Karlsruhe, Germany
Certifications & licenses
Certified Data Annotation Professional (CDAP)
AWS Machine Learning Foundations
Google Cloud AI Platform Fundamentals
Statistics
Experience
Expertise
Qualifications
Profile
Frequently asked questions
Have questions? Find more information here.
Josphat is based in Berlin, Germany.
Josphat speaks the following languages: English (Advanced), German (Intermediate).
Josphat has at least 10 years of experience. During this time, Josphat has worked in at least 3 different roles and for 3 different companies. The average length of individual experience is 3 years and 5 months. Note that Josphat may not have shared all experience and actually has more experience.
Based on recent experience, Josphat would be well-suited for roles such as: Data Annotation Lead, Data Annotation Specialist, Junior Data Annotator.
Josphat's most recent position is Data Annotation Lead at Sigma AI.
In recent years, Josphat has worked for Sigma AI.
Josphat is most experienced in industries like Information Technology, Automotive, and Professional Services.
Josphat is most experienced in business areas like Quality Assurance, Project Management, and Information Technology.
Josphat has recently worked in industries like Automotive and Information Technology.
Josphat has recently worked in business areas like Project Management and Quality Assurance.
Josphat holds a Bachelor in Computer Science from Karlsruhe University.
Josphat has 3 certificates. These include: Certified Data Annotation Professional (CDAP), AWS Machine Learning Foundations, and Google Cloud AI Platform Fundamentals.
The availability of Josphat needs to be confirmed.
Daily rate distribution
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Calculated based on our freelancers’ daily rates as of 7 Sep 2026. Actual rates may vary depending on seniority level, experience, skill specialization, project complexity, and engagement length.
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