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data annotation


High-quality data annotation and categorization is a top priority at Appen. From the first day of a project, we establish a dedicated Quality & Innovation team to manage this process, using a range of standard QA methods and proprietary processes to ensure quality output. We work with you to define quality targets and methods, then manage the projects and workforce to meet or exceed goals — including quality, reporting, and auditing. From multi-content, side-by-side annotation interfaces, to mobile data collection apps, we develop custom tools to support a project, providing you with quality-focused, full-service solutions.

data annotation


Proprietary Appen software tools are hosted in world-class data centers accessible online through industry-standard security protocols. This allows our workers in over 130 countries to access our custom platform, guaranteeing availability. If a project contains information too sensitive to be hosted in the cloud, we can provide air-gapped access, working on annotation projects within an isolated, Appen-run computing facility. These dedicated facilities are secured with ISO and SOC certification, and are supported by business continuity plans to handle any eventuality.

data annotation

Speed & Agility

With a worldwide network of crowd workers in 130 countries, our unique ability to quickly ramp projects up and down based on your needs is a key differentiator at Appen. Our different engagement models are built to handle wide variability in project size, scope, and location. As a data annotation project progresses, unique requirements can emerge. Appen’s engineering teams use agile methodology to rapidly respond to feature development requests.

Text Annotation

Access our team’s deep experience across a wide variety of text types

  • sentiment analysis dataset

    Sentiment Annotation

    To assess attitudes, emotions, and opinions online, it’s important to have the right training data for sentiment analysis. Appen annotators can evaluate sentiment and moderate content on all web platforms, including social media and eCommerce sites, with the ability to tag and report on keywords that are profane, sensitive, neologistic, or misspelled.

  • data annotation services

    Intent Annotation

    As people converse more with human-machine interfaces, machines must be able to understand both natural language and user intent. Appen helps clients train applications and machine learning models via multi-intent data collection and categorization — differentiating intent into key categories including request, command, booking, recommendation, and confirmation.

  • data annotation services

    Query Annotation

    To help our clients build search platforms and products with more relevant search results for customers, Appen annotates a range of queries to evaluate whether they are transactional, informational, or navigational. We also offer a subset service called Address Annotation — identifying which elements of an address query correspond to the street name, city, state, and country.

  • data annotation services

    Co-Reference Annotation

    Captions on the search engine results page (SERP) offer users key clues on which links are most relevant to their searches. Typically, the first interaction with a web result will be through the caption, followed by how well the result matches the caption on the SERP. In fact, almost 35% of search traffic does not result in a click, meaning that users often find what they are looking for directly from a caption. Our evaluation optimizes captions for both the query and the result, offering insight into areas of improvement for better search relevance.

  • semantic annotation

    Semantic Annotation

    Semantic annotation both improves product listings and ensures customers can find the products they’re looking for. This helps turn browsers into buyers. By tagging the various components within product titles and search queries, our semantic annotation services help train your algorithm to recognize those individual parts and improve overall search relevance. As your inventory changes over time, we can help ensure the accuracy and relevance of your site search results.

  • data annotation services

    Named Entity Annotation

    Appen offers a range of named entity annotation services. We help eCommerce clients identify and tag a range of key descriptors, including product name, item number, and much more. We help social media and marketing firms identify entities such as people, places, companies, organizations, and titles to assist with better targeted advertising content. Lastly, government departments and companies including business intelligence firms rely on our services to help identify entities such as people, places, and organizations for analysis.

  • data annotation services

    Other Linguistic Annotation Services

    Appen offers a full range of other common linguistic annotation services including semantic roles and relations, part-of-speech markup, and syntactic and dependency tree-banking annotation.

Audio Annotation

Advance the success of your technology platforms—or machine learning programs—with leading audio annotation services

With over 20 years of experience collecting and processing speech data, audio annotation is one of Appen’s core service offerings. We provide audio annotation services, such as the transcription and time-stamping of speech data, including the transcription of specific pronunciation and intonation, along with the identification of language, dialect, and speaker demographics. Every use case is different, and some require a very specific approach: for example, the tagging of aggressive speech indicators and non-speech sounds like glass breaking for use in security and emergency hotline technology applications.

Image Annotation

Improve your machine learning solutions with high-quality, human-annotated image data for greater precision and accuracy

Image annotation is vital for a wide range of applications, including computer vision, robotic vision, facial recognition, and solutions that rely on machine learning to interpret images. To train these solutions, metadata must be assigned to the images in the form of identifiers, captions, or keywords.

From computer vision systems used by self-driving vehicles and machines that pick and sort produce, to healthcare applications that auto-identify medical conditions, there are many use cases that require high volumes of annotated images. Image annotation increases precision and accuracy by effectively training these systems.

Appen provides a range of image annotation services. Our proprietary image annotation tool lets our team easily categorize or classify objects within an image by assigning it one or more pieces of metadata, from simple categorization to complex image analysis. We can handle multi-phase annotation by building in logic and dependency trees into multiple (unlimited) rounds of annotation, reviewing images in more detail, and building out specific metadata about each object. We can also review for offensive content in images, annotate images to improve search functionality within a client’s image recognition software, and categorize images by quality to improve search content over time.

Our annotation tool allows for a variety of image tagging methods, including bounding box, line and multi-point line, point, polygon and free-form drawing, and categorization. Case studies are available
upon request.

  • image annotation services
  • image annotation services
  • image annotation services
  • image annotation services
video annotation

Video Annotation

Access a full range of video annotation services to improve your AI and machine learning solutions

Appen’s proprietary video annotation tools allow for tagging gestures and facial expressions, frame-by-frame annotation, object tracking, content moderation, and more. For frame annotation, a data annotator uses image annotation features (bounding box, cuboids, points, lines, and multi-segment lines) to markup video frames. Our object tracking service “tracks” previously defined objects in between frames, aiding annotators by pre-populating known object markups in subsequent frames.

We help our clients evaluate video for offensive content and classify videos into different categories like politics, religion, news, or business. Additionally, we can annotate videos in qualitative terms to improve search content functionality and the user experience over time. Finally, we can classify topics, and help clients understand what type of advertising should accompany a particular video while identifying where ad breaks should best occur.

Speech Recognition Database

Access ready-made solutions from Appen to fast-track your project

Appen offers licensable speech recognition databases and speech corpora which you can use to quickly expand your voice recognition products. This gives you immediate access to a complete speech and language database.

Talk to us today to find out more about these high-quality licensable datasets, which cover:

  • Fully transcribed speech recognition databases for broadcast, call center, in-car, and telephony applications
  • Pronunciation lexicons, both general and domain specific (e.g. names, places, and natural numbers)
  • POS-tagged lexicons and thesauri
  • Speech corpora annotated for POS, morphological information, and named entities

Why Appen?

With access to a curated crowd of over 1 million skilled annotators worldwide — in over 130 countries covering more than 180 languages and dialects — Appen is uniquely positioned to provide you with high-quality, human-annotated datasets for your target markets. Join some of the world’s leading organizations and engage Appen to gain access to high volumes of in-market annotated datasets to improve, refine, and further automate your machine learning algorithms.

Contact us today

Read our blog

Visit our blog for additional resources

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