Melanie Gower, 28, works for Asylum Aid, a national charity that provides advice and assistance to asylum seekers.

Telling people I work for a charity always provokes a reaction - not always positive! It seems that everyone has an idea of what they'd like charities to be like, although I do sometimes wonder whether some of these expectations are realistic.

For example, people often tell me that they would give money to charity if they thought it would be directly spent on the cause, rather than on generous staff salaries or expensive marketing material.

People who donate to charity are right to expect that their money will be spent on activities that will make a difference. After all, this is what inspired them to donate in the first place. But this doesn't mean that money spent on staff won't deliver any benefits to their cause.

For a start, the type of work that charities do these days is incredibly varied. Many charities have roles in providing essential services that Governments and public services might have been expected to provide in the past. Some provide assistance with legal advice, healthcare and housing. These can be complex matters, and it is in their clients' interests for charities to recruit people with the experience and expertise necessary to do these jobs.

This can often mean competing for staff who could otherwise work in the public or private sector. This doesn't mean that charities have to offer the same salaries and perks that are on offer elsewhere, but it is unrealistic to expect charities to be able to rely on finding enough suitably-skilled people who are willing to offer their services free.

Charities are also being expected to become more professional in their approach to their work. This isn't a bad thing - after all, people are unlikely to have confidence in giving their support to a charity that looks like it isn't well-organised or professionally run. But it does mean that charities have to allocate time and resources to meeting these standards.

I also think it is wrong to assume that charities can only make a difference by giving direct assistance to people in need. While this work is obviously very important, it is not always the most effective or efficient use of their resources.

As last year's Make Poverty History campaign showed, finding a lasting solution to issues like global poverty and famine requires more than addressing people's immediate needs for food and shelter. It makes sense to employ staff to undertake lobbying and campaigning activities to address the underlying causes of these problems, such as the unfair international trade and debt relief rules. This work might not deliver the same immediate results as distributing emergency aid, but achieving change in this way will benefit many more people than could be helped by direct acts of assistance.

Charities can be a force for positive change in our society. They can draw attention to an issue, help to change public attitudes, or give a voice to people whose interests may otherwise be ignored by decision-makers. The elderly, homeless and disabled people are just some of the groups in society that have benefited from charities acting in this way.

I don't think that all charities are perfect. Those that are perceived to be more concerned with their own preservation rather than the cause they were originally set up to deal with are harmful to everyone in the sector. But don't be too hard on us - with a bit of research I'm sure you'll find we're not all bad!