Within the past few years, several papers have been published which present updated profile ozone trends from the recently revised ground-based Umkehr record <Miller et al., 1995> and the combined Nimbus 7 solar backscattered ultraviolet (SBUV) and NOAA 11 SBUV 2 satellite data record <Hollandsworth et al., 1995; Miller et al., 1996>. Within these papers, however, there has remained an overriding question as to the actual information content of the measurement systems and their ability to detect atmospheric responses. In this paper, we compare the ozone trends and responses to the 11-year solar cycle (derived from model and/or data specifications of these effects) to results of forward model/retrieval algorithm computations through the algorithms. We consider data at northern midlatitudes (30¿--50 ¿N) so that we may compare the satellite results with those of the ground-based systems. Our results indicate that the Umkehr data contain only four independent pieces of information in the vertical and that the SBUV system contains five. In particular, we find that consideration should be restricted to the following regions; Umkehr: the sum of Umkehr layers 1--5, and layers 6, 7, and 8+ (the sum of layers 8 and above), SBUV: the sum of layers 1--5, and layers 6, 7, 8, and 9+ (the sum of layers 9 and above). Additionally, we compare the actual trends and solar coefficients derived in these layers for the periods 1968--1991 and 1979--1991 for the Umkehr and SBUV data. Finally, we include within the latter comparisons the stratospheric aerosol and gas experiment (SAGE) I and II results from Wang et al. <1996> and the computations from the ozonesondes.¿ 1997 American Geophysical Union