The group said in its interim management statement that it saw a good performance in its syndicated services in the first quarter and that the custom business performed in line with expectations.
TNS admitted that the near-term macro economic outlook remained uncertain, particularly in North America, but said that the group believed that the growth potential for the market information industry remains strong.
Although it is still early in the year, TNS said that overall levels of new business activity for the quarter were improved from the previous year.
The group's overall expectations for the year remain unchanged from those given in its 2007 results. TNS said that the proportion of orders secured at the end of the first quarter supported these expectations and "reinforces the group's confidence in the outlook for the full year".
TNS reported revenue growth of 6.3% in its full-year results last month and said that cash generation was strong, allowing the completion of its share buy-back programme.
It also said that in 2008 it would continue to expand internet research coverage in Europe, Asia and Latin America.
The group will issue a trading statement on July 11 ahead of the interim results announcement on August 29.