Many organizations use an anonymous feedback mechanism to get feedback from their employees.
However, if you only emphasize an anonymous feedback mechanism or your team is asking for an anonymous feedback mechanism take it as a HUGE red flag around trust.
The people don't have any safety to talk about their issues with the organization or colleagues in a transparent way. You should do everything you can to provide trust and safety for transparent feedback.
Issues with anonymous feedback
1. Misinterpreted feedback
Anonymous feedback is inherently asynchronous. Usually provided in written form with limited context.
This not feedback, it is data that can highlight a symptom or pattern but should never be taken as specific feedback to immediately make a decision on without further investigation.
If you take the anonymous feedback without filtering through context you may reach the wrong conclusions about the root cause of an issue.
If you're giving or receiving feedback in a transparent way you can immediately start to dig deeper (with empathy) to ensure you understand the full context and can help improve either yourself as a recipient and thank the person who took the time to give you feedback.
2. No opportunity to coach
If you allow people to provide anonymous feedback without discussion and guidance they may focus on people rather than the situation that caused the issue.
This is a well known inherent bias in most people and teams (The fundamental attribution error). You should have a competent facilitator to work through feedback with the people involved in the feedback and the people involved in creating the situation and environment (the leaders). Anonymous feedback makes this difficult.
If the person providing feedback is focusing on criticisms of the person rather than on specific behaviors you should actively be steering them towards identifying the specific behaviors.
You cannot easily change people. Specific behaviors can be changed. These are important skills for anyone working in a team or leading a team to learn.
Benefits of anonymous feedback
Like everything anonymous and transparent feedback are trade-offs. There are advantages to anonymous feedback that shouldn't be ignored. You should have some kind of anonymous feedback mechanism available. Anonymous feedback can be used by a team that are genuinely afraid to speak up about something with their immediate leadership or colleagues.
There are topics that are extremely difficult for an employee that is new or maybe at the start of their career to even mention. Vulnerable employees and targeted people will not be comfortable discussing issues especially if they or their leader hasn't got appropriate training in how to approach them. Things like ethics, safety, whistle-blowing, bullying, uncomfortable peer-pressure, culture issues.
The problem is that when these are received anonymously it can be difficult to identify where the issue is. But it does tell you that the issue exists and that you absolutely need to fix it.
This anonymous feedback mechanism should complement a culture of direct, transparent feedback.
Addressing lack of trust
Talk to the team. You should be able to facilitate a meeting to discover the criteria that would make them comfortable giving direct feedback. Work through why they don't feel safe to discuss things.
This is the harder route for sure, but more valuable for your team and culture in the long term. Expect it to take some time.
Has the team received specific training on conflict resolution? Have they received any training on identifying different perspectives and aligning motivations to understand why they might feel like something is not being done the perfect way?
These don't have to be expensive consultant led trainings but just some sessions on specific issues with a competent facilitator from your organization.
Lead the way - Show how feedback is supposed to work in your organization - If you're an engineering leader then in your meetings talk about how you received feedback from someone, how you empathized and the meaningful change that resulted from the feedback.
Show the team how easy it is to give direct feedback to you. If you don't regularity show vulnerability like this how can you expect the team(s) to?
Anonymous feedback has its place but you should first ensure that there is enough trust in the organization to encourage transparent feedback.
Direct, transparent feedback with empathy should be the primary mechanism for feedback. If it isn't you should start to ask why you're not there and how you can start to improve.
Resource: Radical Candor by Kim Scott is a good book on giving and receiving valuable direct feedback with empathy - Radical Candor - Amazon