Different sources of data provide a generally consistent picture of downward trends in rates of trade union density, presence and coverage. Analysis however raises cause for concern regarding official estimates derived from the Labour Force Survey which underestimate the true extent to which unions are both present in the workplace and recognised by employers in negotiations over the pay and conditions of employees. Whilst the presence of downward trends in union membership is not open to debate, there are many more workers affected by unionisation than one might think based upon a casual glance at the official statistics.