Did tax flattening affect RRSP contributions?

In 1988 marginal personal income tax rates changed in Canada, for some indi viduals by reasonably substantial amounts. In this note a large sample of t ax-filer data is examined and the conclusion is drawn that, when attention is paid to the possible confounding of marginal tax rate and non-linear inc ome effects, there is no convincing evidence that the tax rate changes affe cted contributions to Registered Retirement Saving Plans (RRSPs).