Primary source materials are not neutral documents, and as such, can carry the biases, prejudices, and opinions of the person, peoples, group, or organization, that created it. There are also certain groups of people, cultures, and sub-cultures, that have not recorded their history in a way that is considered traditional by a colonial and westernized society, either by choice or by necessity. As a result, it can sometimes be difficult to locate primary source materials about certain groups of people, or topics, from certain points in time.
Some examples:
- It was illegal to send anything "obscene" by mail until 1958 in the United States and until 1959 in Canada. As a result, there is very little surviving correspondence from people with marginalized sexual or gender identities.
- People who have experienced homelessness or precarious housing are less likely to have had the ability to keep long-term records and subsequently donate them to an archive.
- Records of enduring value have been destroyed by people, or groups, in positions of power. In the past records have been destroyed by donors that revealed that family members were gay, records that document genocidal acts are often at least partially destroyed by the perpetrators, and colonial administration records are often relocated or destroyed after the colonized peoples gain liberation and/or independence.
- Historically, married women typically changed their last names and were often referred to using their husband's names in publications. This can make tracing the identity of married women in published and unpublished materials difficult.
- Colonial, western society previously only considered "recorded" histories to be valid. Archives have only recently begun collecting and commissioning oral histories.
- Historical newspapers and books carry the perspectives and biases of the people that wrote them. Prejudiced ideas and subjects of study, such as eugenics, may feature in published materials without acknowledging the harm that they caused. In these cases it is also less common to have perspectives from the people who were harmed.