How to recruit the best data annotators for your AI projects?


Data annotators are often considered to be unsung heroes who are behind the rapid advances in artificial intelligence. Every day, we discover incredible new products designed using AI. One of the latest being the Apple Vision Pro, a futuristic helmet that relies heavily on technologies such as Computer Vision.
Behind the scenes of AI, Data annotator teams play a very important role in the development of systems. These professionals tag/tag data and ensure the quality and accuracy of the annotated data. In short, the accuracy of AI models depends largely on the different data annotation methods used by these annotators (also called “Data Labelers”) in the AI development cycle.
Whether you are looking for in-house data annotators, freelancers or external professionals from third-party companies specializing in data annotation for AI, you need the best experts capable of carrying out your AI projects. That's why we've compiled a comprehensive guide that covers all the aspects to consider when hiring data annotators, or when preparing a tender for dataset labeling. Let's go!

What is a data annotator?
Let's start with the basics. What is a data annotator or Data Labeler ? A data annotator is a person who labels and tags data used to train machine learning models (i.e. to produce training data for AI). Working as a team, these professionals meticulously review and interpret data and add labels, text annotations, and metadata that help machine learning algorithms understand patterns and make accurate predictions.
To feed an AI model with data, a significant amount of raw or unstructured data is first collected. Then, data annotators go through a tedious process to label and categorize data and make it more structured. Once the data annotation is complete, the organized data is used to “feed” the AI model and train it to independently replicate these same tasks of detection or recognition of objects.
In short, Data annotators play a key role in training AI models by annotating and tagging large amounts of data For example, the functioning of chatbots depends largely on large volumes of text. pre-treated and labelled. When the data annotator labels samples of textual data to add indications about their meaning and concrete intent, it helps the chatbot learn properly by giving it accurate contextual indications.
Data annotators also validate annotated data to ensure accuracy when training models. As a result, there is a need to build teams of expert data annotators that you can trust and who can contribute to the success of AI projects.
Today, data annotators help develop highly capable AI systems that power a broad range of applications, such as natural language processing (NLP), image recognition, and sentiment analysis. This implies that the ability to analyze, label, and tag data is the key skill to look for in a data annotator. Often misperceived (some will say: “anyone or any clickworker can annotate images, this work does not deserve to be paid properly”), this job requires technical skills, rigor as well as a significant amount of work capacity to produce “ground truth” datasets of quality.
What are the main responsibilities of a data annotator?
Data annotators are involved in various data collection and processing responsibilities. We have identified two key responsibilities of a data annotator, namely the taging/tagging of data and the validation of annotated data.
1. Data tagging and tagging
The main responsibility of data annotators is to label data types through tools that enable labeling and tagging. It involves associating metadata with a set of thematic data, just like adding subtitles to a movie. The job of annotators is to accurately assign labels and tags to a wide variety of unstructured data types, such as videos, images, or text.
Data labeling essentially requires the data annotation specialist to assign feeling scores to texts or images or to categorize images into relevant classes using objects such as Bounding Box Or Polygons. The task of annotating or labeling data requires marking specific characteristics or attributes within the data.
In short, labeling and tagging data allow artificial intelligence models to classify objects, recognize patterns, and provide accurate results by learning from quality data.
2. Validating annotated data
Another important responsibility of data annotators is to validate annotated data. This involves validating the quality, accuracy, and consistency of the labelled data.
Validating annotated data is important because it eliminates inaccuracies, biases, and inconsistencies in the training data. Therefore, data annotators help validate annotated data and ensure that models are trained with reliable data sets.
Concretely, what are the daily tasks of a data annotator?
While taging/tagging and validation are the core responsibilities of a data annotator, it is essential to delve deeper into their daily tasks to have a complete understanding of their role. Here is an overview of the tasks that these data professionals perform on a daily basis:
Analyzing the data
Data annotators meticulously review and dissect raw data to identify unique attributes, patterns, and characteristics that will make it easier for AI to process the annotation. This analysis ensures that the annotator understands the context and complexity of the data, leading to more accurate and meaningful annotations.
Develop guidelines
To maintain consistency and accuracy in the annotation process, data annotators create comprehensive guidelines and instruction manuals. These resources serve as a reference for other annotators, ensuring that everyone follows a unified approach and adheres to the same standards. Sometimes, it is useful to develop a register of errors and atypical cases, updated over the course of the project, which will serve as a reference base for dealing with the most complex cases.
Assign labels and other tags
With an eye for detail and the rigor characteristic of this profession, data annotators assign relevant labels and tags to raw and unstructured data. This process involves categorizing, classifying, and adding metadata to data, making it more accessible and valuable for machine learning algorithms.
Validate annotated data
Data annotators review and verify the quality, accuracy, and consistency of annotated data, ensuring that it meets project requirements and standards. This step may involve identifying and correcting errors, resolving ambiguities, and providing feedback to other annotators to improve overall data quality.
Interacting with other teams
Collaboration is an important aspect of the role of a data annotator. Data Labelers work closely with Data Scientists, Data Engineers, and other stakeholders to ensure that annotation activities are executed effectively. This collaboration may involve discussing the goals of the project, updating the progress, and resolving any challenges or concerns through daily exchanges (for example: “I don't know how to classify this medical device, can we help me?” or “the image is very difficult to read, should I annotate or is it better to ignore this image. I am afraid to impact the results of the model with approximate data).
In addition to these responsibilities, data annotators are responsible for maintaining the confidentiality of sensitive data and adhering to strict data security protocols. They should handle data carefully, ensuring that it is protected from unauthorized access, use, or breach. By doing this, data annotators maintain the integrity of the project and products using AI.
Different strategies for finding data annotators
Now that we are clear about the role and responsibilities of experts in data processing and annotation, let's move on to the main point of this guide: How do I hire the best experts in data annotation? If you've already explored the possibility of using existing datasets or preparing your own data for your AI, you've certainly run into this challenge. Do I need to annotate 5,000 images or 30,000 to get results? Is my data set diverse enough? Where can I find equipment to process my data: it is a job that seems extremely long, repetitive and painstaking to me. That must be extremely expensive!
Don't worry, we're here to help. There are various strategies for finding data annotators. If you talk to the older ones, they should probably suggest that you use Amazon MechanicalTurk or platforms like Upwork. Is it really the best way to prepare your data? This may have been the case 10 years ago, but nothing is less certain at the time of GPT chat And of Mistral AI.
Let's look at each of these strategies and assess their pros and cons:
1. Recruiting and training internal data annotators
The first option to consider when building your data annotation team is to hire data annotators in-house. This approach consists in recruiting individuals who will work exclusively for your company, devoting their time and expertise to your projects. By having a dedicated team in-house, you can foster a stronger commitment to the project and develop a deeper understanding of its complexities as team members focus only on the goals and objectives of your organization.
One of the main benefits of this option is the improved collaboration and communication offered. In-house data annotators work closely with other team members. This proximity facilitates seamless collaboration and open communication channels, allowing them to address challenges, share information, and streamline the annotation process more effectively. So your team can work together cohesively, ensuring everyone is on the same page and working toward the same goals.
Another benefit of having an in-house team is improved data security. By keeping sensitive data within your organization, you can reduce the risk of unauthorized access or data breaches. In-house data annotators are more likely to be well-informed about your organization's data security protocols and to adhere to strict privacy guidelines, ensuring that your valuable data remains protected. This does not mean that it is absolutely necessary to secure data by neglecting your annotation software. We have already encountered customers using devices that are not very ergonomic, requiring the use of a certain type of equipment or screen. It takes us back to the 2000s, with a hint of nostalgia perhaps... You have to find a compromise between ergonomics and the security of your data (not all data deserves to be secure!).

Finally, hiring data annotators in-house is a long-term investment in your organization's data annotation capabilities. As they gain experience and expertise in your specific field, they become valuable assets that can contribute to multiple projects and help drive your business initiatives based on data. By encouraging and developing your internal team, you can create a solid foundation for future success in your annotation and data analysis projects.
On the other hand, in-house data annotators also present challenges. It is sometimes reassuring to have an internal team, on site. But it's also expensive. Some companies have asked us to use temporary workers or even interns to carry out certification tasks. If you want quality data, you may be disappointed. Not that interns and temporary workers are not (potentially) qualified for annotation work. You may face a strong risk of disengagement from staff who are little or not interested in the business of data for AI, which will impact the quality of your data. It is therefore rarely recommended to entrust certification tasks to your Data Scientists trainees, even if it seems practical! The latter will very quickly disengage due to the complex and laborious nature of the task (sometimes considered not very interesting). Instead, entrust them with tasks of Sourcing of AI providers! You will save time and quality.
Benefits of in-house data annotators
(+) Better understanding of the project
(+) Effective Collaboration and Communication
(+) Higher data security
Disadvantages of in-house data annotators
(-) Time-consuming recruitment process
(-) Requires resources and efforts for training
(-) Very expensive to maintain an internal team/ Onshore, sometimes with the risk of discouraging overqualified teams (example of the Data Scientist intern who becomes a Data Labeler unwittingly).
In short, having a team of in-house data annotators has both pros and cons. So the final decision depends on your needs. If you want a dedicated team that remains committed to the project, if you have significant resources: building a team of in-house data annotators seems possible. But don't dream: if you're dealing with medical data, it's unlikely that a doctor will agree to annotate your data at an hourly rate similar to Amazon SageMaker or Clickworker. If not, you can opt for outsourced solutions. Two solutions: freelancers and specialized service providers (such as Innovatiana).
2. Recruit freelance consultants for your annotation tasks
Freelance consultants, data processing specialists, experts or not AI experts, represent another popular choice for businesses that want to hire data annotators on demand, per project. This approach allows organizations to engage with professionals who sometimes have specific expertise that matches their project needs, without the long-term commitment associated with internal hiring.
One of the main benefits of hiring freelance consultants is profitability and return on investment. By hiring freelancers, you can access the same level of expertise as in-house data annotators, but at a considerably lower cost. This flexibility allows your organization to adapt its data annotation efforts according to project requirements, without the financial constraints of maintaining a permanent workforce.
Additionally, working with freelance Data Labelers can save your business valuable time in training and onboarding. The market is full of professionals with diverse expertise and skills, allowing you to find the right person for your project with minimal effort. So, you can quickly build a team of freelancers with experience in data annotation who can start working right away and deliver high-quality results in your desired timeframe.

In addition to cost savings and efficiency, consultants have specialized knowledge and experience. They may have worked on projects that are competing with your business. They bring a wealth of knowledge and best practices to your project. This diverse expertise can be invaluable in meeting the challenges of annotating complex data and ensuring that your project benefits from the latest techniques and innovations in the field.
Finally, engaging with freelance data annotation experts gives your organization the flexibility to adapt to changing project requirements. As your data annotation needs change, you can easily increase or decrease the size of your team, depending on the scope and complexity of the project. This adaptability ensures that you always have the right resources at your disposal, without the constraints of a fixed workforce.
However, recruiting freelancers also has some disadvantages. The biggest one is the data security risk. You have to trust these consultants. To do this, we recommend signing a non-disclosure agreement. Additionally, you may not be able to get the same quality of work as with an internal team, because the internal team is more committed to your project and better understands the goals. Also, the use of freelance consultants requires a significant effort to qualify and mobilize the team... while it can work well on small data sets, building a team of more than 5 people who do not know each other, have never worked together, will require an investment as significant as internal recruitment before obtaining results...
Benefits of Hiring Freelance Consultants
(+) Profitable
(+) Quick access to expertise and specialized skills
(+) Scalable and flexible
Disadvantages of hiring freelance consultants
(-) Data Security Risks
(-) Uncertainty about the quality of work and collaborative work mechanisms
(-) Less committed/responsible
Therefore, it is important to find a balance between profitability and the quality of work if you opt for freelance data annotation specialists. In addition, be sure to check their qualification correctly and to monitor/assess the quality of work regularly.
3. Outsourced professionals from third party companies
The third strategy for finding data annotators is to outsource to third party companies that specialize in Data Labeling. These organizations have a workforce of well-trained and experienced data annotation professionals who can be hired on demand, providing a flexible and effective solution for your data annotation needs.
Outsourcing data annotators to third party companies has numerous benefits, the most important of which is access to first-class expertise and experience in the field of data annotation. These professionals are constantly updated with the latest techniques and tools, ensuring that they provide high-quality data annotation tasks that comply with industry best practices. By harnessing their in-depth knowledge and skills, you can ensure that your projects have accurate annotations, which in turn drives the success of your data-based initiatives.
In addition, AI annotation service providers offer a well-structured methodology that includes workflows and appropriate processes. This structured approach ensures that your annotation projects will be managed professionally, with clear communication channels, well-defined milestones, and rigorous quality control measures in place. As a result, you can expect transparent and effective collaboration that results in timely project delivery and high-quality results.
Another advantage of outsourcing data annotators to these providers is the ability to adapt your data annotation efforts according to project requirements. These organizations generally maintain a workforce of professionals with diverse skills (specialist medical annotator, specialists in certain rare languages, etc.), allowing you to quickly increase or reduce the size of your team as needed. This flexibility ensures that you always have the right resources at your disposal, without having to maintain a permanent in-house workforce.
Finally, partnering with a reputable third-party data annotation company can help alleviate concerns about data security and privacy. These organizations often have strict data protection measures in place, ensuring that your sensitive data remains safe and protected throughout the annotation process. By entrusting your data annotation needs to a reliable external partner, you can focus on your goals with peace of mind.
However, be careful: some of these service providers will offer you to lock your service with a proprietary and paid software solution (“are you using a free platform or an internal development to process your data? This is not effective, rather take a subscription to our solution (invoiced at the rate of XXX EUR per user). At Innovatiana, we believe that the best solution to produce quality “ground truth” data is to train qualified professionals. While we have our opinions on the various existing platforms (some functionalities are very much appreciated and influence AI developments), we refuse an overly closed model that would impose the use of one solution over another.
Benefits of outsourcing to specialized AI annotation providers
(+) Instant access to experienced and knowledgeable data annotators
(+) Overall inexpensive for the quality level, cost-effective
(+) Professionally managed annotation projects
(+) High quality annotation
Disadvantages of outsourcing to specialized AI annotation providers
(-) Possibility of differences in points of view concerning your AI pipelines
(-) For some service providers, locking services with proprietary labelling tools (software solutions)
In summary, outsourcing data annotators to third-party companies offers an effective solution for organizations that want to integrate qualified professionals in a short period of time. This approach offers numerous advantages, such as access to first-class expertise, a well-structured methodology, and the ability to adapt resources according to project requirements. However, it is essential to carefully assess the pros and cons of outsourcing before making a decision, as this method may not be appropriate for all organizations or projects.
On the one hand, outsourcing data annotators can offer significant benefits in terms of cost savings, time efficiency, and access to specialized knowledge. By partnering with a reputable third-party company like Innovatiana, you can access a vast pool of experienced professionals who master the latest annotation tools and techniques, ensuring high-quality results for your projects.
How do I find effective data annotators? Our advice
Below, we've listed 3 ways to find the best data annotators for your AI projects:
1. Use Data Labeling outsourcing specialists
You can contact outsourced data annotation professionals who have teams of trained and experienced Data Labelers and Data Labeling Managers. This will help you get quick access to experienced data annotators and save significant time and resources. Businesses like Innovatiana or Sama are specialized in data annotation services and offer first-class services with a focus on certain geographies.
2. Post job offers on dedicated platforms
You can post jobs for data annotators on LinkedIn, Indeed, Glassdoor, or other popular platforms. This will of course require more time, and is recommended if you have significant resources and work in sensitive industries (medicine, automotive, etc.).
3. Freelance or crowdsourcing platforms
You can search for data annotators on freelance platforms, like Upwork, Fiverr and others like it. You can post job requirements or search for data annotators yourself. However, keep in mind that the quality level may lack consistency because freelance consultant consultants are potentially poorly trained or over-sell their skills to sell work on these highly competitive platforms.
All of the above methods can help you easily find data annotators that match your project needs. However, be sure to focus on finding data annotators with the right skills by carefully evaluating their expertise and experience.
7 more factors to consider when hiring data annotators
When hiring data annotators, consider the following factors for recruiting the best talent :
In conclusion
The role of data annotators has become increasingly important in AI projects. Therefore, it is important to recruit the right talent who can lead your AI projects to success. Above, we discussed in detail how to hire data annotators using a variety of approaches, such as internal recruitment, freelance services, and outsourcing. Choose the approach of your choice and start your search today!
Each approach has its unique advantages, from the dedicated commitment and deep understanding of the project offered by in-house data annotators or to the professional methodology found in data annotation service providers. By carefully evaluating your project needs, organizational goals and available resources, you can determine the most appropriate approach for your specific AI needs.
As you embark on your search for ideal data annotators, remember that The quality of your annotated data will have a profound impact on the performance and accuracy of your AI models. Therefore, it is critical to prioritize factors such as domain expertise, familiarity with the latest annotation tools and techniques, and excellent communication skills.
💡 A last point that is important to us at Innovatiana is ethics: this is unfortunately a factor that is often overlooked by some service providers or platforms. We refuse anti-competitive practices consisting in offering excessively low or not transparent rates for data annotation services. These practices hide working conditions for annotators that are incompatible with our ESG policy.
In summary, the importance of data annotators in defining the future of AI cannot be underestimated. By following the guidelines and considerations presented in this discussion, you will be well-equipped to make informed decisions and recruit top talent to boost your AI projects. Choose the approach that fits your goals and start your search for exceptional data annotators today.