Which has more inductive effect: an aldehyde or a carboxylic acid? A chemistry reference book that I have been reading gives the order of inductive effect ($-I$) as follows:



While the Wikipedia page on inductive effect gives the following order:

$\ce{-NH3+} &gt; \ce{-NO2} &gt; \ce{-SO2R} &gt; \ce{-CN} &gt; \ce{-SO3H} &gt; \ce{-CHO} &gt; \ce{-CO} &gt; \ce{-COOH} &gt; \ce{-COCl}&gt; \ce{-CONH2} &gt;
\ce{-F} &gt; \ce{-Cl} &gt; \ce{-Br} &gt; \ce{-I} &gt; \ce{-OR} &gt; \ce{-OH} &gt; \ce{-NH2} &gt; \ce{-C6H5} &gt;\ce{-CH=CH2} &gt;\ce{-H}$

The reference book has $\ce{COOH}$ ahead of $\ce{CHO}$ but Wikipedia has it the other way around. Which source is correct?
I believe the Wiki page is more accurate, because the Hammett Equation substituent constants (para) indicate -CHO should be more "electron withdrawing" than -COOH, but there is little reason to use such lists as "absolute" - I think they are simply good guidelines for reactivity. 

I looked at the data in this link: https://www.bluffton.edu/homepages/facstaff/bergerd/classes/CEM311/handouts/sigmas.pdf 

However, substituent constants are not absolute proof of "inductive effect" and it is difficult to conclude from such data that a particular substituent is more "inductively" electron withdrawing than another. To do that, we would need a model (or a set of compounds, equivalently) where we can achieve separability of sigma and pi electrons.