https://community.jmp.com/t5/Discussions/Cannot-select-use-4PL-Rodbard-curve-fit/m-p/919263#M107852 <P>Could you have the same reason as here&nbsp;<LI-MESSAGE title="Why can't use 'Fit Logistic 4P Rodbard' ?" uid="714764" url="https://community.jmp.com/t5/Discussions/Why-can-t-use-Fit-Logistic-4P-Rodbard/m-p/714764#U714764" discussion_style_icon_css="lia-mention-container-editor-message lia-img-icon-forum-thread lia-fa-icon lia-fa-forum lia-fa-thread lia-fa"></LI-MESSAGE>&nbsp;?</P> <BLOCKQUOTE> <P><EM>That model is disallowed when you have a dose equal to zero.</EM></P> </BLOCKQUOTE> Sat, 13 Dec 2025 07:12:49 GMT jthi 2025-12-13T07:12:49Z https://community.jmp.com/t5/Discussions/Cannot-select-use-4PL-Rodbard-curve-fit/m-p/919204#M107846 <P>Hi there,</P> <P>I am trying to fit a dose-response curve to the Rodbard 4PL model. I have 3 columns, my Response, Regressor, and a weighting. The option for Rodbard is greyed out and I cannot select it. all other 4PL fits are available so I'm not sure why the one I need is not available?&nbsp;</P> <P>Kindly,</P> <P>TK</P> Fri, 12 Dec 2025 21:05:14 GMT https://community.jmp.com/t5/Discussions/Cannot-select-use-4PL-Rodbard-curve-fit/m-p/919204#M107846 CurseOfCheetah8 2025-12-12T21:05:14Z https://community.jmp.com/t5/Discussions/Cannot-select-use-4PL-Rodbard-curve-fit/m-p/919263#M107852 <P>Could you have the same reason as here&nbsp;<LI-MESSAGE title="Why can't use 'Fit Logistic 4P Rodbard' ?" uid="714764" url="https://community.jmp.com/t5/Discussions/Why-can-t-use-Fit-Logistic-4P-Rodbard/m-p/714764#U714764" discussion_style_icon_css="lia-mention-container-editor-message lia-img-icon-forum-thread lia-fa-icon lia-fa-forum lia-fa-thread lia-fa"></LI-MESSAGE>&nbsp;?</P> <BLOCKQUOTE> <P><EM>That model is disallowed when you have a dose equal to zero.</EM></P> </BLOCKQUOTE> Sat, 13 Dec 2025 07:12:49 GMT https://community.jmp.com/t5/Discussions/Cannot-select-use-4PL-Rodbard-curve-fit/m-p/919263#M107852 jthi 2025-12-13T07:12:49Z